Improve upgradability of defconfig files

- Switch to two-pass reading of the config file to track both (a) the
option's value and (b) if the option has been explicitly called out in
the .config being processed.
- Split off per-version functions into separate files.
- Add a README with some guidelines on writing new upgrade scripts.

Signed-off-by: Alexey Neyman <stilor@att.net>

4 files changed, 565 insertions, 492 deletions

diff --git a/scripts/upgrade/README b/scripts/upgrade/README
new file mode 100644
index 0000000..51760ea
--- /dev/null
+++ b/scripts/upgrade/README
@@ -0,0 +1,23 @@
+Upgrade scripts for specific versions of the config file.
+Each script must define a function `upgrade` that can
+assume `${opt}` and `${val}` variables set on input. On
+output, if `${opt}` is unset - so will be the corresponding
+option.
+
+One thing to keep in mind is that this script may be invoked
+on full config - or on a defconfig. Do not assume that all
+options will be present! If an option is not specified, use
+the value it had as a default for the fallback; to check if
+it has been specified, use `$selected_opts` associative
+array to check if it has been present in the config file
+(otherwise, you an option not being set after sourcing the
+previous version of the config is ambiguous - it could be
+that the option is called out as `# CT_FOO is not set` (i.e.
+selected as false) or not present at all (i.e. selected as
+default).
+
+If it is not possible to determine the settings of an option
+because a different controlling option is not set, either
+err out (see CT_LIBC_UCLIBC_CUSTOM in v0 for an example)
+or select a sane default and issue a warning (see CT_GDB_CUSTOM
+in v0 for an example).
diff --git a/scripts/upgrade/v0 b/scripts/upgrade/v0
new file mode 100644
index 0000000..68dfca0
--- /dev/null
+++ b/scripts/upgrade/v0
@@ -0,0 +1,351 @@
+# vim: set filetype=sh :
+
+# Upgrade from v0: select Linaro as the vendor if a Linaro version was selected
+# (in v0, both GNU and Linaro versions were combined in a single list). GNU is
+# the default, leave it to olddefconfig to select it if we don't see a Linaro version.
+# We don't depend on CT_xxx_SHOW_LINARO symbols: they just enabled showing Linaro
+# versions in that list, but it may have been GNU version that was actually selected.
+select_linaro()
+{
+    if is_set; then
+        echo "# CT_${1}_USE_GNU is not set"
+        echo "CT_${1}_USE_LINARO=y"
+    fi
+}
+
+# Upgrade from version 0 (which is 1.23, as released) to version 1
+# (current state of master as of 2019/01/20). Upgrades in the interim
+# versions may be broken.
+upgrade()
+{
+    case "${opt}" in
+    CT_ARCH_alpha|CT_ARCH_arm|CT_ARCH_avr|CT_ARCH_m68k|CT_ARCH_microblaze|\
+    CT_ARCH_mips|CT_ARCH_nios2|CT_ARCH_powerpc|CT_ARCH_s390|CT_ARCH_sh|\
+    CT_ARCH_sparc|CT_ARCH_x86|CT_ARCH_xtensa|\
+    CT_BINUTILS_binutils|\
+    CT_CC_gcc|\
+    CT_COMP_TOOLS_autoconf|CT_COMP_TOOLS_automake|CT_COMP_TOOLS_libtool|\
+    CT_COMP_TOOLS_m4|CT_COMP_TOOLS_make|\
+    CT_DEBUG_duma|CT_DEBUG_gdb|CT_DEBUG_ltrace|CT_DEBUG_strace|\
+    CT_KERNEL_bare_metal|CT_KERNEL_linux|CT_KERNEL_windows|\
+    CT_LIBC_avr_libc|CT_LIBC_glibc|CT_LIBC_musl|CT_LIBC_newlib|CT_LIBC_none|\
+    CT_LIBC_uClibc)
+        # Renamed to upper-case
+        replace ${opt^^}
+        ;;
+    CT_ARCH_XTENSA_CUSTOM_NAME)
+        replace CT_OVERLAY_NAME
+        ;;
+    CT_ARCH_XTENSA_CUSTOM_OVERLAY_LOCATION)
+        replace CT_OVERLAY_LOCATION
+        ;;
+    CT_LIBC_mingw)
+        # Renamed to MINGW_W64
+        opt=CT_LIBC_MINGW_W64
+        ;;
+    CT_ARCH_*_AVAILABLE|CT_KERNEL_*_AVAILABLE|CT_LIBC_*_AVAILABLE)
+        # Previously used "backend selectors". Autogenerated, no warning
+        unset opt
+        ;;
+    CT_CONFIGURE_has_*)
+        # Configure-detected build machine options. Drop, will use current.
+        unset opt
+        ;;
+    CT_*_or_later)
+        # Automatically selected version constraints. Drop, will auto-select current ones.
+        unset opt
+        ;;
+    CT_BACKEND_ARCH|CT_BACKEND_KERNEL|CT_BACKEND_LIBC|CT_IS_A_BACKEND)
+        warning "Option ${opt} is no longer supported, dropping"
+        unset opt
+        ;;
+    CT_*_SHOW_LINARO)
+        # Used to just include Linaro versions into the list. We'll infer whether Linaro is
+        # actually used from the actual version selected, below.
+        unset opt
+        ;;
+    CT_CC_GCC_4_8|CT_CC_GCC_4_9|CT_CC_GCC_5|CT_CC_GCC_6|\
+    CT_LIBC_NEWLIB_2_0|CT_LIBC_NEWLIB_2_1|CT_LIBC_NEWLIB_2_2|CT_LIBC_NEWLIB_2_3|CT_LIBC_NEWLIB_2_4|CT_LIBC_NEWLIB_2_5)
+        # In 1.23.0, each package had its own ad-hoc version constraints. Drop, new ones
+        # will be autoselected.
+        unset opt
+        ;;
+    # Custom location: translate to the new framework. No generic way to interpret the version
+    # string user may have configured; just warn him to select it manually.
+    CT_BINUTILS_CUSTOM)
+        warning_if_set "Assuming custom location contains GNU sources; edit the configuration if it was Linaro version"
+        replace CT_BINUTILS_SRC_CUSTOM
+        ;;
+    CT_CC_GCC_CUSTOM)
+        warning_if_set "Assuming custom location contains GNU sources; edit the configuration if it was Linaro version"
+        replace CT_GCC_SRC_CUSTOM
+        ;;
+    CT_CC_GCC_CUSTOM_LOCATION)
+        replace CT_GCC_CUSTOM_LOCATION
+        ;;
+    CT_ELF2FLT_CUSTOM)
+        replace CT_ELF2FLT_SRC_CUSTOM
+        ;;
+    CT_ELF2FLT_GIT)
+        if is_set; then
+            echo "CT_ELF2FLT_SRC_DEVEL=y"
+        fi
+        replace CT_ELF2FLT_DEVEL_VCS_git
+        ;;
+    CT_ELF2FLT_GIT_CSET)
+        replace CT_ELF2FLT_DEVEL_REVISION
+        ;;
+    CT_GDB_CUSTOM)
+        warning_if_set "Assuming custom location contains GNU sources; edit the configuration if it was Linaro version"
+        replace CT_GDB_SRC_CUSTOM
+        ;;
+    CT_KERNEL_LINUX_CUSTOM)
+        replace CT_LINUX_SRC_CUSTOM
+        ;;
+    CT_KERNEL_LINUX_CUSTOM_LOCATION)
+        replace CT_LINUX_CUSTOM_LOCATION
+        ;;
+    CT_LIBC_AVR_LIBC_CUSTOM)
+        replace CT_AVR_LIBC_SRC_CUSTOM
+        ;;
+    CT_LIBC_AVR_LIBC_CUSTOM_LOCATION)
+        replace CT_AVR_LIBC_CUSTOM_LOCATION
+        ;;
+    CT_LIBC_GLIBC_CUSTOM)
+        warning_if_set "Assuming custom location contains GNU sources; edit the configuration if it was Linaro version"
+        replace CT_GLIBC_SRC_CUSTOM
+        ;;
+    CT_LIBC_GLIBC_CUSTOM_LOCATION)
+        replace CT_GLIBC_CUSTOM_LOCATION
+        ;;
+    CT_LIBC_MUSL_CUSTOM)
+        replace CT_MUSL_SRC_CUSTOM
+        ;;
+    CT_LIBC_MUSL_CUSTOM_LOCATION)
+        replace CT_MUSL_CUSTOM_LOCATION
+        ;;
+    CT_LIBC_NEWLIB_CUSTOM)
+        warning_if_set "Assuming custom location contains GNU sources; edit the configuration if it was Linaro version"
+        replace CT_NEWLIB_SRC_CUSTOM
+        ;;
+    CT_LIBC_NEWLIB_CUSTOM_LOCATION)
+        replace CT_NEWLIB_CUSTOM_LOCATION
+        ;;
+    CT_LIBC_UCLIBC_CUSTOM)
+        if is_set; then
+            if [ "${selected_opts[CT_LIBC_UCLIBC_CUSTOM_UCLIBC]+set}" != "set" ]; then
+                error "This option requires full config file, not defconfig"
+            elif [ "${CT_LIBC_UCLIBC_CUSTOM_UCLIBC}" = "y" ]; then
+                replace CT_UCLIBC_USE_UCLIBC_ORG
+            else
+                replace CT_UCLIBC_USE_UCLIBC_NG_ORG
+            fi
+        fi
+        ;;
+    CT_LIBC_UCLIBC_CUSTOM_UCLIBC)
+        replace CT_UCLIBC_SRC_CUSTOM
+        ;;
+    CT_LIBC_UCLIBC_CUSTOM_UCLIBC_NG)
+        replace CT_UCLIBC_NG_SRC_CUSTOM
+        ;;
+    CT_LIBC_UCLIBC_CUSTOM_UCLIBC_NG_OLD)
+        warning_if_set "uClibc-NG versions before 1.0.15 no longer supported"
+        replace CT_UCLIBC_NG_SRC_CUSTOM
+        ;;
+    CT_LIBC_UCLIBC_CUSTOM_LOCATION)
+        if [ "${CT_LIBC_UCLIBC_CUSTOM_UCLIBC}" = "y" ]; then
+            replace CT_UCLIBC_CUSTOM_LOCATION
+        else
+            replace CT_UCLIBC_NG_CUSTOM_LOCATION
+        fi
+        ;;
+    CT_WINAPI_V_DEVEL)
+        replace CT_MINGW_W64_SRC_DEVEL
+        ;;
+    CT_WINAPI_V_select)
+        # Internal selector
+        unset opt
+        ;;
+    CT_BINUTILS_CUSTOM_VERSION|CT_CC_GCC_CUSTOM_VERSION|CT_ELF2FLT_CUSTOM_VERSION|CT_KERNEL_LINUX_CUSTOM_VERSION|\
+    CT_LIBC_AVR_LIBC_CUSTOM_VERSION|CT_LIBC_GLIBC_CUSTOM_VERSION|CT_LIBC_MUSL_CUSTOM_VERSION|\
+    CT_LIBC_NEWLIB_CUSTOM_VERSION|CT_LIBC_UCLIBC_CUSTOM_VERSION|CT_GDB_CUSTOM_VERSION)
+        warning_if_set "Cannot automatically convert custom version; edit configuration to select it"
+        unset opt
+        ;;
+    CT_CC_GCC_VERSION|CT_CC_VERSION|CT_KERNEL_VERSION|CT_WINAPI_VERSION|CT_LIBC_VERSION)
+        # Auto-selected; the symbol was just renamed
+        unset opt
+        ;;
+    CT_LIBC_glibc_family)
+        # Internal selector, not user-visible
+        unset opt
+        ;;
+    CT_LIBC_ADDONS_LIST)
+        warning_if_set "Support for custom add-ons has been removed. If using libidn add-on, edit the configuration."
+        ;;
+    CT_LIBC_DISABLE_VERSIONING)
+        replace CT_GLIBC_DISABLE_VERSIONING
+        ;;
+    CT_LIBC_ENABLE_FORTIFIED_BUILD)
+        replace CT_GLIBC_ENABLE_FORTIFIED_BUILD
+        ;;
+    CT_LIBC_GLIBC_CONFIGPARMS|CT_LIBC_GLIBC_EXTRA_CFLAGS|CT_LIBC_GLIBC_EXTRA_CONFIG_ARRAY|\
+    CT_LIBC_GLIBC_FORCE_UNWIND|CT_LIBC_GLIBC_KERNEL_VERSION_AS_HEADERS|CT_LIBC_GLIBC_KERNEL_VERSION_CHOSEN|\
+    CT_LIBC_GLIBC_KERNEL_VERSION_NONE|CT_LIBC_GLIBC_MIN_KERNEL|CT_LIBC_GLIBC_MIN_KERNEL_VERSION)
+        replace CT_GLIBC_${opt#CT_LIBC_GLIBC_}
+        ;;
+    CT_LIBC_LOCALES)
+        replace CT_GLIBC_LOCALES
+        ;;
+    CT_LIBC_OLDEST_ABI)
+        replace CT_GLIBC_OLDEST_ABI
+        ;;
+    CT_LIBC_GLIBC_NEEDS_PORTS|CT_LIBC_GLIBC_PORTS_EXTERNAL|CT_LIBC_GLIBC_USE_PORTS)
+        # Auto-selected
+        unset opt
+        ;;
+    CT_LIBC_UCLIBC_LOCALES_PREGEN_DATA)
+        warning_if_set "Support for pregenerated locales in uClibc has been removed"
+        unset opt
+        ;;
+    # Trivial version replacements
+    CT_AUTOMAKE_V_1_11_1)           replace CT_AUTOMAKE_V_1_11_6;;
+    CT_AUTOMAKE_V_1_11_6)           replacement_for CT_AUTOMAKE_V_1_11_1;;
+    CT_AUTOMAKE_V_1_14)             replace CT_AUTOMAKE_V_1_14_1;;
+    CT_AUTOMAKE_V_1_15)             replace CT_AUTOMAKE_V_1_15_1;;
+    CT_BINUTILS_V_2_26)             replace CT_BINUTILS_V_2_26_1;;
+    CT_BINUTILS_V_2_28)             replace CT_BINUTILS_V_2_28_1;;
+    CT_BINUTILS_LINARO_V_2_23_2)    select_linaro BINUTILS; replace CT_BINUTILS_LINARO_V_2_23_2_2013_10_4;;
+    CT_BINUTILS_LINARO_V_2_24)      select_linaro BINUTILS; replace CT_BINUTILS_LINARO_V_2_24_0_2014_11_2;;
+    CT_BINUTILS_LINARO_V_2_25)      select_linaro BINUTILS; replace CT_BINUTILS_LINARO_V_2_25_0_2015_01_2;;
+    CT_CC_GCC_V_4_8_5)              replace CT_GCC_V_4_8_5;;
+    CT_CC_GCC_V_4_9_4)              replace CT_GCC_V_4_9_4;;
+    CT_CC_GCC_V_5_4_0)              replace CT_GCC_V_5_5_0;;
+    CT_CC_GCC_V_6_3_0)              replace CT_GCC_V_6_5_0;;
+    CT_CC_GCC_V_linaro_4_8)         select_linaro GCC; replace CT_GCC_LINARO_V_4_8_2015_06;;
+    CT_CC_GCC_V_linaro_4_9)         select_linaro GCC; replace CT_GCC_LINARO_V_4_9_2017_01;;
+    CT_CC_GCC_V_linaro_5_4)         select_linaro GCC; replace CT_GCC_LINARO_V_5_5_2017_10;;
+    CT_CC_GCC_V_linaro_6_3)         select_linaro GCC; replace CT_GCC_LINARO_V_6_4_2018_05;;
+    CT_CLOOG_V_0_18_0)              replace CT_CLOOG_V_0_18_1;;
+    CT_CLOOG_V_0_18_1)              replacement_for CT_CLOOG_V_0_18_0;;
+    CT_EXPAT_V_2_2_0)               replace CT_EXPAT_V_2_2_6;; # 2.2.6 was not available in ct-ng 1.23.0 - no replacement_for
+    CT_GDB_V_6_8a)                  replace CT_GDB_V_6_8A;;
+    CT_GDB_V_7_0a)                  replace CT_GDB_V_7_0_1A;;
+    CT_GDB_V_7_0_1a)                replace CT_GDB_V_7_0_1A;;
+    CT_GDB_V_7_1a)                  replace CT_GDB_V_7_1A;;
+    CT_GDB_V_7_2a)                  replace CT_GDB_V_7_2A;;
+    CT_GDB_V_7_3a)                  replace CT_GDB_V_7_3A;;
+    CT_GDB_V_7_4)                   replace CT_GDB_V_7_4_1;;
+    CT_GDB_V_7_7)                   replace CT_GDB_V_7_7_1;;
+    CT_GDB_V_7_8|CT_GDB_V_7_8_1)    replace CT_GDB_V_7_8_2;;
+    CT_GDB_V_7_8_2)                 replacement_for CT_GDB_V_7_8 CT_GDB_V_7_8_1;;
+    CT_GDB_V_7_9)                   replace CT_GDB_V_7_9_1;;
+    CT_GDB_V_7_10)                  replace CT_GDB_V_7_10_1;;
+    CT_GDB_V_linaro_7_3)            select_linaro GDB; replace CT_GDB_LINARO_V_7_3_2011_12;;
+    CT_GDB_V_linaro_7_4)            select_linaro GDB; replace CT_GDB_LINARO_V_7_4_2012_06;;
+    CT_GDB_V_linaro_7_5)            select_linaro GDB; replace CT_GDB_LINARO_V_7_5_2012_12;;
+    CT_GDB_V_linaro_7_6)            select_linaro GDB; replace CT_GDB_LINARO_V_7_6_1_2013_10;;
+    CT_GDB_V_linaro_7_7)            select_linaro GDB; replace CT_GDB_LINARO_V_7_7_1_2014_06_1;;
+    CT_GDB_V_linaro_7_7_1)          select_linaro GDB; replace CT_GDB_LINARO_V_7_7_1_2014_06_1;;
+    CT_GDB_V_linaro_7_8)            select_linaro GDB; replace CT_GDB_LINARO_V_7_8_2014_09;;
+    CT_GMP_V_4_3_0|CT_GMP_V_4_3_1)  replace CT_GMP_V_4_3_2;;
+    CT_GMP_V_4_3_2)                 replacement_for CT_GMP_V_4_3_0 CT_GMP_V_4_3_1;;
+    CT_GMP_V_5_0_1|CT_GMP_V_5_0_2)  replace CT_GMP_V_5_0_5;; # 5.0.5 not in ct-ng 1.23.0
+    CT_GMP_V_5_1_1)                 replace CT_GMP_V_5_1_3;;
+    CT_GMP_V_5_1_3)                 replacement_for CT_GMP_V_5_1_1;;
+    CT_GMP_V_6_0_0)                 replace CT_GMP_V_6_0_0A;; # 6.0.0a not in ct-ng 1.23.0
+    CT_GMP_V_6_1_0)                 replace CT_GMP_V_6_1_2;;
+    CT_GMP_V_6_1_2)                 replacement_for CT_GMP_V_6_1_0;;
+    CT_ISL_V_0_11_1)                replace CT_ISL_V_0_11_2;;
+    CT_ISL_V_0_14)                  replace CT_ISL_V_0_14_1;;
+    CT_KERNEL_V_2_6_32|CT_KERNEL_V_2_6_33|CT_KERNEL_V_2_6_34|CT_KERNEL_V_2_6_35|\
+    CT_KERNEL_V_2_6_36|CT_KERNEL_V_2_6_37|CT_KERNEL_V_2_6_38|CT_KERNEL_V_2_6_39|\
+    CT_KERNEL_V_3_0|CT_KERNEL_V_3_1|CT_KERNEL_V_3_2|CT_KERNEL_V_3_3|CT_KERNEL_V_3_4|CT_KERNEL_V_3_5|\
+    CT_KERNEL_V_3_6|CT_KERNEL_V_3_7|CT_KERNEL_V_3_8|CT_KERNEL_V_3_9|CT_KERNEL_V_3_10|CT_KERNEL_V_3_11|\
+    CT_KERNEL_V_3_12|CT_KERNEL_V_3_13|CT_KERNEL_V_3_14|CT_KERNEL_V_3_15|CT_KERNEL_V_3_16|\
+    CT_KERNEL_V_3_17|CT_KERNEL_V_3_18|CT_KERNEL_V_3_19|\
+    CT_KERNEL_V_4_0|CT_KERNEL_V_4_1|CT_KERNEL_V_4_2|CT_KERNEL_V_4_3|CT_KERNEL_V_4_4|\
+    CT_KERNEL_V_4_5|CT_KERNEL_V_4_6|CT_KERNEL_V_4_7|CT_KERNEL_V_4_8|CT_KERNEL_V_4_9|CT_KERNEL_V_4_10)
+                                    replace CT_LINUX_${opt#CT_KERNEL_};;
+    CT_LIBC_AVR_LIBC_V_1_8_0)       replace CT_AVR_LIBC_V_1_8_1;;
+    CT_LIBC_AVR_LIBC_V_1_8_1)       replace CT_AVR_LIBC_V_1_8_1;;
+    CT_LIBC_AVR_LIBC_V_2_0_0)       replace CT_AVR_LIBC_V_2_0_0;;
+    CT_LIBC_GLIBC_V_2_12_1|CT_LIBC_GLIBC_V_2_12_2|CT_LIBC_GLIBC_V_2_13|CT_LIBC_GLIBC_V_2_14|\
+    CT_LIBC_GLIBC_V_2_14_1|CT_LIBC_GLIBC_V_2_15|CT_LIBC_GLIBC_V_2_16_0|CT_LIBC_GLIBC_V_2_17|\
+    CT_LIBC_GLIBC_V_2_18|CT_LIBC_GLIBC_V_2_19|CT_LIBC_GLIBC_V_2_20|CT_LIBC_GLIBC_V_2_21|\
+    CT_LIBC_GLIBC_V_2_22|CT_LIBC_GLIBC_V_2_23|CT_LIBC_GLIBC_V_2_24|CT_LIBC_GLIBC_V_2_25)
+                                    replace CT_GLIBC_${opt#CT_LIBC_GLIBC_};;
+    CT_LIBC_GLIBC_LINARO_V_2_20)    replace CT_GLIBC_LINARO_V_2_20_2014_11;;
+    CT_LIBC_MUSL_V_1_1_15|CT_LIBC_MUSL_V_1_1_16)
+                                    replace CT_MUSL_${opt#CT_LIBC_MUSL_};;
+    CT_LIBC_NEWLIB_V_1_17_0|CT_LIBC_NEWLIB_V_1_18_0|CT_LIBC_NEWLIB_V_1_19_0|CT_LIBC_NEWLIB_V_1_20_0|\
+    CT_LIBC_NEWLIB_V_2_0_0|CT_LIBC_NEWLIB_V_2_1_0|CT_LIBC_NEWLIB_V_2_2_0|CT_LIBC_NEWLIB_V_2_3_0|\
+    CT_LIBC_NEWLIB_V_2_4_0|CT_LIBC_NEWLIB_V_2_5_0)
+                                    replace CT_NEWLIB_${opt#CT_LIBC_NEWLIB_};;
+    CT_LIBC_NEWLIB_LINARO_V_2_1_0)  select_linaro NEWLIB; replace CT_NEWLIB_LINARO_V_2_1_0_2014;;
+    CT_LIBC_NEWLIB_LINARO_V_2_2_0)  select_linaro NEWLIB; replace CT_NEWLIB_LINARO_V_2_2_0_2015;;
+    CT_LIBELF_V_0_8_12)             replace CT_LIBELF_V_0_8_13;;
+    CT_LIBELF_V_0_8_13)             replacement_for CT_LIBELF_V_0_8_12;;
+    CT_M4_V_1_4_13|CT_M4_V_1_4_17)  replace CT_M4_V_1_4_18;;
+    CT_M4_V_1_4_18)                 replacement_for CT_M4_V_1_4_13 CT_M4_V_1_4_17;;
+    CT_MPC_V_0_8_1)                 replace CT_MPC_V_0_8_2;;
+    CT_MPC_V_0_8_2)                 replacement_for CT_MPC_V_0_8_1;;
+    CT_MPC_V_1_0|CT_MPC_V_1_0_1|CT_MPC_V_1_0_2)
+                                    replace CT_MPC_V_1_0_3;;
+    CT_MPC_V_1_0_3)                 replacement_for CT_MPC_V_1_0 CT_MPC_V_1_0_1 CT_MPC_V_1_0_2;;
+    CT_MPFR_V_2_4_0|CT_MPFR_V_2_4_1)
+                                    replace CT_MPFR_V_2_4_2;;
+    CT_MPFR_V_2_4_2)                replacement_for CT_MPFR_V_2_4_0 CT_MPFR_V_2_4_1;;
+    CT_MPFR_V_3_0_0)                replace CT_MPFR_V_3_0_1;;
+    CT_MPFR_V_3_0_1)                replacement_for CT_MPFR_V_3_0_0;;
+    CT_MPFR_V_3_1_0|CT_MPFR_V_3_1_2|CT_MPFR_V_3_1_3|CT_MPFR_V_3_1_5)
+                                    replace CT_MPFR_V_3_1_6;;
+    CT_MPFR_V_3_1_6)                replacement_for CT_MPFR_V_3_1_0 CT_MPFR_V_3_1_2 CT_MPFR_V_3_1_3 CT_MPFR_V_3_1_5;;
+    CT_STRACE_V_4_5_18|CT_STRACE_V_4_5_19)
+                                    replace CT_STRACE_V_4_5_20;;
+    CT_STRACE_V_4_5_20)             replacement_for CT_STRACE_V_4_5_18 CT_STRACE_V_4_5_19;;
+    CT_LIBC_UCLIBC_NG_V_1_0_20|CT_LIBC_UCLIBC_NG_V_1_0_21|CT_LIBC_UCLIBC_NG_V_1_0_22)
+                                    if is_set; then
+                                        echo "CT_UCLIBC_USE_UCLIBC_NG_ORG=y"
+                                    fi
+                                    replace CT_UCLIBC_NG_V_1_0_25
+                                    ;;
+    CT_LIBC_UCLIBC_V_0_9_33_2)
+                                    if is_set; then
+                                        echo "CT_UCLIBC_USE_UCLIBC_ORG=y"
+                                    fi
+                                    replace CT_UCLIBC_V_0_9_33_2
+                                    ;;
+    CT_WINAPI_V_2_0_7|CT_WINAPI_V_2_0_7|CT_WINAPI_V_2_0_9)
+                                    replace CT_MINGW_W64_V_V2_0_10;;
+    CT_WINAPI_V_3_0_0)              replace CT_MINGW_W64_V_V3_0_0;;
+    CT_WINAPI_V_3_1_0)              replace CT_MINGW_W64_V_V3_1_0;;
+    CT_WINAPI_V_3_2_0)              replace CT_MINGW_W64_V_V3_2_0;;
+    CT_WINAPI_V_3_3_0)              replace CT_MINGW_W64_V_V3_3_0;;
+    CT_WINAPI_V_4_0_0|CT_WINAPI_V_4_0_1|CT_WINAPI_V_4_0_2|CT_WINAPI_V_4_0_3|\
+    CT_WINAPI_V_4_0_4|CT_WINAPI_V_4_0_5|CT_WINAPI_V_4_0_6)
+                                    replace CT_MINGW_W64_V_V4_0_6;;
+    CT_WINAPI_V_5_0_0|CT_WINAPI_V_5_0_1)
+                                    replace CT_MINGW_W64_V_V5_0_3;;
+
+    # Misc
+    CT_CLOOG_NEEDS_AUTORECONF)
+        # Was unused in 1.23, just drop
+        unset opt
+        ;;
+    CT_PATCH_SINGLE)
+        # Internal selector in 1.23
+        unset opt
+        ;;
+    CT_PATCH_BUNDLED_FALLBACK_LOCAL|CT_PATCH_LOCAL_FALLBACK_BUNDLED)
+        warning_if_set "Fallback patch order has been removed"
+        ;;
+    CT_CC_GCC_TARGET_FINAL)
+        warning_if_set "Option removed"
+        ;;
+    CT_COMPLIBS|CT_COMPLIBS_NEEDED|CT_CC_GCC_latest)
+        # Internal selectors
+        unset opt
+        ;;
+    esac
+}
diff --git a/scripts/upgrade/v1 b/scripts/upgrade/v1
new file mode 100644
index 0000000..0794722
--- /dev/null
+++ b/scripts/upgrade/v1
@@ -0,0 +1,114 @@
+# vim: set filetype=sh :
+
+# Upgrade v1 -> v2: several packages had their config options renamed
+# to leave only the relevant part - so that further upgrades of, say,
+# GCC 6.5.0 to 6.6.0 do not result in config changes.
+upgrade()
+{
+    case "${opt}" in
+    CT_ANDROID_NDK_V_R10E|CT_ANDROID_NDK_V_R11C|CT_ANDROID_NDK_V_R12B|\
+    CT_ANDROID_NDK_V_R13B|CT_ANDROID_NDK_V_R14B|CT_ANDROID_NDK_V_R15C|\
+    CT_ANDROID_NDK_V_R16B|CT_ANDROID_NDK_V_R17C)
+        replace "${opt%[A-Z]}"
+        ;;
+    CT_AUTOMAKE_V_1_11_6|CT_AUTOMAKE_V_1_14_1|\
+    CT_AUTOMAKE_V_1_15_1|CT_AUTOMAKE_V_1_16_1)
+        replace "${opt%_[0-9]}"
+        ;;
+    CT_BINUTILS_LINARO_V_2_23_2_2013_10_4|CT_BINUTILS_LINARO_V_2_24_0_2014_11_2|\
+    CT_BINUTILS_LINARO_V_2_25_0_2015_01_2)
+        replace "${opt%_[0-9]_201[345]*}"
+        ;;
+    CT_BINUTILS_V_2_23_2|CT_BINUTILS_V_2_25_1|CT_BINUTILS_V_2_26_1|\
+    CT_BINUTILS_V_2_28_1|CT_BINUTILS_V_2_29_1|CT_BINUTILS_V_2_31_1)
+        replace "${opt%_[0-9]}"
+        ;;
+    CT_DTC_V_1_4_7)
+        replace CT_DTC_V_1_4
+        ;;
+    CT_EXPAT_V_2_1_1|CT_EXPAT_V_2_2_6)
+        replace "${opt%_[0-9]}"
+        ;;
+    CT_GCC_LINARO_V_4_8_2015_06|CT_GCC_LINARO_V_4_9_2017_01)
+        replace "${opt%_201[57]*}"
+        ;;
+    CT_GCC_LINARO_V_5_5_2017_10|CT_GCC_LINARO_V_6_4_2018_05|\
+    CT_GCC_LINARO_V_7_3_2018_05)
+        replace "${opt%_[0-9]_201[78]*}"
+        ;;
+    CT_GCC_V_4_8_5|CT_GCC_V_4_9_4)
+        replace "${opt%_[0-9]}"
+        ;;
+    CT_GCC_V_5_5_0|CT_GCC_V_6_5_0|CT_GCC_V_7_4_0|CT_GCC_V_8_2_0)
+        replace "${opt%_[0-9]_[0-9]}"
+        ;;
+    CT_GDB_LINARO_V_7_3_2011_12|CT_GDB_LINARO_V_7_4_2012_06|CT_GDB_LINARO_V_7_5_2012_12|\
+    CT_GDB_LINARO_V_7_7_2014_05|CT_GDB_LINARO_V_7_8_2014_09)
+        replace "${opt%_201[57]*}"
+        ;;
+    CT_GDB_LINARO_V_7_6_1_2013_10|CT_GDB_LINARO_V_7_7_1_2014_06_1)
+        replace "${opt%_[0-9]_201[345]*}"
+        ;;
+
+    CT_GDB_V_6_8A|CT_GDB_V_7_1A|CT_GDB_V_7_2A)
+        replace "${opt%A}"
+        ;;
+    CT_GDB_V_7_0_1A)
+        replace CT_GDB_V_7_0
+        ;;
+    CT_GDB_V_7_3_1|CT_GDB_V_7_4_1|CT_GDB_V_7_5_1|CT_GDB_V_7_6_1|CT_GDB_V_7_7_1|\
+    CT_GDB_V_7_8_2|CT_GDB_V_7_9_1|CT_GDB_V_7_10_1|CT_GDB_V_7_11_1|CT_GDB_V_7_12_1|\
+    CT_GDB_V_8_0_1|CT_GDB_V_8_1_1)
+        replace "${opt%_[0-9]}"
+        ;;
+    CT_GLIBC_LINARO_V_2_20_2014_11)
+        replace CT_GLIBC_LINARO_V_2_20
+        ;;
+    CT_GMP_V_4_3_2|CT_GMP_V_5_0_5|CT_GMP_V_5_1_3|CT_GMP_V_6_0_0A|CT_GMP_V_6_1_2)
+        replace "${opt%_[0-9]*}"
+        ;;
+    CT_ISL_V_0_11_2|CT_ISL_V_0_12_2|CT_ISL_V_0_14_1|CT_ISL_V_0_16_1|CT_ISL_V_0_17_1)
+        replace "${opt%_[0-9]}"
+        ;;
+    CT_LIBELF_V_0_8_13)
+        replace CT_LIBELF_V_0_8
+        ;;
+    CT_LIBTOOL_V_2_4_6)
+        replace CT_LIBTOOL_V_2_4
+        ;;
+    CT_M4_V_1_4_18)
+        replace CT_M4_V_1_4
+        ;;
+    CT_MAKE_V_4_2_1)
+        replace CT_MAKE_V_4_2
+        ;;
+    CT_MINGW_W64_V_V2_0_10|CT_MINGW_W64_V_V3_0_0|CT_MINGW_W64_V_V3_1_0|CT_MINGW_W64_V_V3_2_0|\
+    CT_MINGW_W64_V_V3_3_0|CT_MINGW_W64_V_V4_0_6|CT_MINGW_W64_V_V5_0_3|CT_MINGW_W64_V_V6_0_0)
+        replace "${opt%_[0-9]}"
+        ;;
+    CT_MPC_V_0_8_2|CT_MPC_V_1_0_3|CT_MPC_V_1_1_0)
+        replace "${opt%_[0-9]}"
+        ;;
+    CT_MPFR_V_2_4_2|CT_MPFR_V_3_0_1|CT_MPFR_V_3_1_6|CT_MPFR_V_4_0_1)
+        replace "${opt%_[0-9]}"
+        ;;
+    CT_NEWLIB_LINARO_V_2_1_0_2014|CT_NEWLIB_LINARO_V_2_2_0_2015)
+        replace "${opt%_[0-9]_201[345]*}"
+        ;;
+    CT_NEWLIB_V_1_17_0|CT_NEWLIB_V_1_18_0|CT_NEWLIB_V_1_19_0|CT_NEWLIB_V_1_20_0|CT_NEWLIB_V_2_0_0|\
+    CT_NEWLIB_V_2_1_0|CT_NEWLIB_V_2_2_0|CT_NEWLIB_V_2_3_0|CT_NEWLIB_V_2_4_0|CT_NEWLIB_V_2_5_0|\
+    CT_NEWLIB_V_3_0_0)
+        replace "${opt%_[0-9]}"
+        ;;
+
+    CT_CLOOG_HAS_WITH_GMP_ISL_OSL|CT_CLOOG_0_18_or_later|CT_CLOOG_0_18_or_older|\
+    CT_CLOOG_REQUIRE_0_18_or_later|CT_CLOOG_REQUIRE_0_18_or_older|\
+    CT_CLOOG_REQUIRE_later_than_0_18|CT_CLOOG_REQUIRE_older_than_0_18|\
+    CT_CLOOG_later_than_0_18|CT_CLOOG_older_than_0_18|CT_GCC_REQUIRE_4_9_2_or_later|\
+    CT_GCC_REQUIRE_4_9_2_or_older|CT_GCC_REQUIRE_later_than_4_9_2|\
+    CT_GCC_REQUIRE_older_than_4_9_2|CT_GCC_4_9_2_or_later|CT_GCC_4_9_2_or_older|\
+    CT_GCC_BUG_61144|CT_GCC_later_than_4_9_2|CT_GCC_older_than_4_9_2)
+        unset opt # No longer used auto-selectors
+        ;;
+    esac
+}
diff --git a/scripts/version-check.sh b/scripts/version-check.sh
index ccadfe7..f49b1d8 100644
--- a/scripts/version-check.sh
+++ b/scripts/version-check.sh
@@ -39,6 +39,12 @@ EOF
     fi
 fi
 
+# From now on, we're running actual upgrade, not just a check. Preserve the CT_xxx
+# variables that we need using a different prefix so that we can unset the stale
+# values at each iteration.
+MY_LIB_DIR="${CT_LIB_DIR}"
+MY_CONFIG_VERSION_CURRENT="${CT_CONFIG_VERSION_CURRENT}"
+
 is_set()
 {
     if [ "x${val+set}" = "xset" ]; then
@@ -60,6 +66,13 @@ warning()
     echo "WARN ${opt:+:: ${opt} }:: $1" >&2
 }
 
+error()
+{
+     # $opt comes from the caller
+    echo " ERR ${opt:+:: ${opt} }:: $1" >&2
+    exit 1
+}
+
 warning_if_set()
 {
     if is_set; then
@@ -97,509 +110,85 @@ replacement_for()
     done
 }
 
-# Upgrade from v0: select Linaro as the vendor if a Linaro version was selected
-# (in v0, both GNU and Linaro versions were combined in a single list). GNU is
-# the default, leave it to olddefconfig to select it if we don't see a Linaro version.
-# We don't depend on CT_xxx_SHOW_LINARO symbols: they just enabled showing Linaro
-# versions in that list, but it may have been GNU version that was actually selected.
-select_linaro()
-{
-    if is_set; then
-        echo "# CT_${1}_USE_GNU is not set"
-        echo "CT_${1}_USE_LINARO=y"
-    fi
-}
-
-
-### Per-version upgrade drivers. Called with ${opt} and ${val} set,
-### may modify these variables.
-### FIXME: perhaps, split these functions into per-version files in scripts/upgrade/{0,1,...}
-
-# Upgrade from version 0 (which is 1.23, as released) to version 1
-# (current state of master as of 2019/01/20). Upgrades in the interim
-# versions may be broken.
-upgrade_v0()
+# Helper: takes ${ln} in the caller's environment and sets ${opt} and ${val}
+# accordingly. Returns 0 if this line was an option, 1 otherwise.
+set_opt_and_val()
 {
-    case "${opt}" in
-    CT_ARCH_alpha|CT_ARCH_arm|CT_ARCH_avr|CT_ARCH_m68k|CT_ARCH_microblaze|\
-    CT_ARCH_mips|CT_ARCH_nios2|CT_ARCH_powerpc|CT_ARCH_s390|CT_ARCH_sh|\
-    CT_ARCH_sparc|CT_ARCH_x86|CT_ARCH_xtensa|\
-    CT_BINUTILS_binutils|\
-    CT_CC_gcc|\
-    CT_COMP_TOOLS_autoconf|CT_COMP_TOOLS_automake|CT_COMP_TOOLS_libtool|\
-    CT_COMP_TOOLS_m4|CT_COMP_TOOLS_make|\
-    CT_DEBUG_duma|CT_DEBUG_gdb|CT_DEBUG_ltrace|CT_DEBUG_strace|\
-    CT_KERNEL_bare_metal|CT_KERNEL_linux|CT_KERNEL_windows|\
-    CT_LIBC_avr_libc|CT_LIBC_glibc|CT_LIBC_musl|CT_LIBC_newlib|CT_LIBC_none|\
-    CT_LIBC_uClibc)
-        # Renamed to upper-case
-        replace ${opt^^}
-        ;;
-    CT_ARCH_XTENSA_CUSTOM_NAME)
-        replace CT_OVERLAY_NAME
-        ;;
-    CT_ARCH_XTENSA_CUSTOM_OVERLAY_LOCATION)
-        replace CT_OVERLAY_LOCATION
-        ;;
-    CT_LIBC_mingw)
-        # Renamed to MINGW_W64
-        opt=CT_LIBC_MINGW_W64
-        ;;
-    CT_ARCH_*_AVAILABLE|CT_KERNEL_*_AVAILABLE|CT_LIBC_*_AVAILABLE)
-        # Previously used "backend selectors". Autogenerated, no warning
-        unset opt
-        ;;
-    CT_CONFIGURE_has_*)
-        # Configure-detected build machine options. Drop, will use current.
-        unset opt
-        ;;
-    CT_*_or_later)
-        # Automatically selected version constraints. Drop, will auto-select current ones.
-        unset opt
-        ;;
-    CT_BACKEND_ARCH|CT_BACKEND_KERNEL|CT_BACKEND_LIBC|CT_IS_A_BACKEND)
-        warning "Option ${opt} is no longer supported, dropping"
-        unset opt
-        ;;
-    CT_*_SHOW_LINARO)
-        # Used to just include Linaro versions into the list. We'll infer whether Linaro is
-        # actually used from the actual version selected, below.
-        unset opt
-        ;;
-    CT_CC_GCC_4_8|CT_CC_GCC_4_9|CT_CC_GCC_5|CT_CC_GCC_6|\
-    CT_LIBC_NEWLIB_2_0|CT_LIBC_NEWLIB_2_1|CT_LIBC_NEWLIB_2_2|CT_LIBC_NEWLIB_2_3|CT_LIBC_NEWLIB_2_4|CT_LIBC_NEWLIB_2_5)
-        # In 1.23.0, each package had its own ad-hoc version constraints. Drop, new ones
-        # will be autoselected.
-        unset opt
-        ;;
-    # Custom location: translate to the new framework. No generic way to interpret the version
-    # string user may have configured; just warn him to select it manually.
-    CT_BINUTILS_CUSTOM)
-        warning_if_set "Assuming custom location contains GNU sources; edit the configuration if it was Linaro version"
-        replace CT_BINUTILS_SRC_CUSTOM
-        ;;
-    CT_CC_GCC_CUSTOM)
-        warning_if_set "Assuming custom location contains GNU sources; edit the configuration if it was Linaro version"
-        replace CT_GCC_SRC_CUSTOM
-        ;;
-    CT_CC_GCC_CUSTOM_LOCATION)
-        replace CT_GCC_CUSTOM_LOCATION
-        ;;
-    CT_ELF2FLT_CUSTOM)
-        replace CT_ELF2FLT_SRC_CUSTOM
-        ;;
-    CT_ELF2FLT_GIT)
-        if is_set; then
-            echo "CT_ELF2FLT_SRC_DEVEL=y"
-        fi
-        replace CT_ELF2FLT_DEVEL_VCS_git
-        ;;
-    CT_ELF2FLT_GIT_CSET)
-        replace CT_ELF2FLT_DEVEL_REVISION
-        ;;
-    CT_GDB_CUSTOM)
-        warning_if_set "Assuming custom location contains GNU sources; edit the configuration if it was Linaro version"
-        replace CT_GDB_SRC_CUSTOM
-        ;;
-    CT_KERNEL_LINUX_CUSTOM)
-        replace CT_LINUX_SRC_CUSTOM
-        ;;
-    CT_KERNEL_LINUX_CUSTOM_LOCATION)
-        replace CT_LINUX_CUSTOM_LOCATION
-        ;;
-    CT_LIBC_AVR_LIBC_CUSTOM)
-        replace CT_AVR_LIBC_SRC_CUSTOM
-        ;;
-    CT_LIBC_AVR_LIBC_CUSTOM_LOCATION)
-        replace CT_AVR_LIBC_CUSTOM_LOCATION
-        ;;
-    CT_LIBC_GLIBC_CUSTOM)
-        warning_if_set "Assuming custom location contains GNU sources; edit the configuration if it was Linaro version"
-        replace CT_GLIBC_SRC_CUSTOM
-        ;;
-    CT_LIBC_GLIBC_CUSTOM_LOCATION)
-        replace CT_GLIBC_CUSTOM_LOCATION
-        ;;
-    CT_LIBC_MUSL_CUSTOM)
-        replace CT_MUSL_SRC_CUSTOM
-        ;;
-    CT_LIBC_MUSL_CUSTOM_LOCATION)
-        replace CT_MUSL_CUSTOM_LOCATION
-        ;;
-    CT_LIBC_NEWLIB_CUSTOM)
-        warning_if_set "Assuming custom location contains GNU sources; edit the configuration if it was Linaro version"
-        replace CT_NEWLIB_SRC_CUSTOM
-        ;;
-    CT_LIBC_NEWLIB_CUSTOM_LOCATION)
-        replace CT_NEWLIB_CUSTOM_LOCATION
-        ;;
-    CT_LIBC_UCLIBC_CUSTOM)
-        if is_set; then
-            if [ "${CT_LIBC_UCLIBC_CUSTOM_UCLIBC}" = "y" ]; then
-                replace CT_UCLIBC_USE_UCLIBC_ORG
-            else
-                replace CT_UCLIBC_USE_UCLIBC_NG_ORG
-            fi
-        fi
-        ;;
-    CT_LIBC_UCLIBC_CUSTOM_UCLIBC)
-        replace CT_UCLIBC_SRC_CUSTOM
-        ;;
-    CT_LIBC_UCLIBC_CUSTOM_UCLIBC_NG)
-        replace CT_UCLIBC_NG_SRC_CUSTOM
-        ;;
-    CT_LIBC_UCLIBC_CUSTOM_UCLIBC_NG_OLD)
-        warning_if_set "uClibc-NG versions before 1.0.15 no longer supported"
-        replace CT_UCLIBC_NG_SRC_CUSTOM
-        ;;
-    CT_LIBC_UCLIBC_CUSTOM_LOCATION)
-        if [ "${CT_LIBC_UCLIBC_CUSTOM_UCLIBC}" = "y" ]; then
-            replace CT_UCLIBC_CUSTOM_LOCATION
-        else
-            replace CT_UCLIBC_NG_CUSTOM_LOCATION
-        fi
-        ;;
-    CT_WINAPI_V_DEVEL)
-        replace CT_MINGW_W64_SRC_DEVEL
-        ;;
-    CT_WINAPI_V_select)
-        # Internal selector
-        unset opt
-        ;;
-    CT_BINUTILS_CUSTOM_VERSION|CT_CC_GCC_CUSTOM_VERSION|CT_ELF2FLT_CUSTOM_VERSION|CT_KERNEL_LINUX_CUSTOM_VERSION|\
-    CT_LIBC_AVR_LIBC_CUSTOM_VERSION|CT_LIBC_GLIBC_CUSTOM_VERSION|CT_LIBC_MUSL_CUSTOM_VERSION|\
-    CT_LIBC_NEWLIB_CUSTOM_VERSION|CT_LIBC_UCLIBC_CUSTOM_VERSION|CT_GDB_CUSTOM_VERSION)
-        warning_if_set "Cannot automatically convert custom version; edit configuration to select it"
-        unset opt
-        ;;
-    CT_CC_GCC_VERSION|CT_CC_VERSION|CT_KERNEL_VERSION|CT_WINAPI_VERSION|CT_LIBC_VERSION)
-        # Auto-selected; the symbol was just renamed
-        unset opt
-        ;;
-    CT_LIBC_glibc_family)
-        # Internal selector, not user-visible
-        unset opt
-        ;;
-    CT_LIBC_ADDONS_LIST)
-        warning_if_set "Support for custom add-ons has been removed. If using libidn add-on, edit the configuration."
-        ;;
-    CT_LIBC_DISABLE_VERSIONING)
-        replace CT_GLIBC_DISABLE_VERSIONING
-        ;;
-    CT_LIBC_ENABLE_FORTIFIED_BUILD)
-        replace CT_GLIBC_ENABLE_FORTIFIED_BUILD
-        ;;
-    CT_LIBC_GLIBC_CONFIGPARMS|CT_LIBC_GLIBC_EXTRA_CFLAGS|CT_LIBC_GLIBC_EXTRA_CONFIG_ARRAY|\
-    CT_LIBC_GLIBC_FORCE_UNWIND|CT_LIBC_GLIBC_KERNEL_VERSION_AS_HEADERS|CT_LIBC_GLIBC_KERNEL_VERSION_CHOSEN|\
-    CT_LIBC_GLIBC_KERNEL_VERSION_NONE|CT_LIBC_GLIBC_MIN_KERNEL|CT_LIBC_GLIBC_MIN_KERNEL_VERSION)
-        replace CT_GLIBC_${opt#CT_LIBC_GLIBC_}
-        ;;
-    CT_LIBC_LOCALES)
-        replace CT_GLIBC_LOCALES
-        ;;
-    CT_LIBC_OLDEST_ABI)
-        replace CT_GLIBC_OLDEST_ABI
-        ;;
-    CT_LIBC_GLIBC_NEEDS_PORTS|CT_LIBC_GLIBC_PORTS_EXTERNAL|CT_LIBC_GLIBC_USE_PORTS)
-        # Auto-selected
-        unset opt
-        ;;
-    CT_LIBC_UCLIBC_LOCALES_PREGEN_DATA)
-        warning_if_set "Support for pregenerated locales in uClibc has been removed"
-        unset opt
-        ;;
-    # Trivial version replacements
-    CT_AUTOMAKE_V_1_11_1)           replace CT_AUTOMAKE_V_1_11_6;;
-    CT_AUTOMAKE_V_1_11_6)           replacement_for CT_AUTOMAKE_V_1_11_1;;
-    CT_AUTOMAKE_V_1_14)             replace CT_AUTOMAKE_V_1_14_1;;
-    CT_AUTOMAKE_V_1_15)             replace CT_AUTOMAKE_V_1_15_1;;
-    CT_BINUTILS_V_2_26)             replace CT_BINUTILS_V_2_26_1;;
-    CT_BINUTILS_V_2_28)             replace CT_BINUTILS_V_2_28_1;;
-    CT_BINUTILS_LINARO_V_2_23_2)    select_linaro BINUTILS; replace CT_BINUTILS_LINARO_V_2_23_2_2013_10_4;;
-    CT_BINUTILS_LINARO_V_2_24)      select_linaro BINUTILS; replace CT_BINUTILS_LINARO_V_2_24_0_2014_11_2;;
-    CT_BINUTILS_LINARO_V_2_25)      select_linaro BINUTILS; replace CT_BINUTILS_LINARO_V_2_25_0_2015_01_2;;
-    CT_CC_GCC_V_4_8_5)              replace CT_GCC_V_4_8_5;;
-    CT_CC_GCC_V_4_9_4)              replace CT_GCC_V_4_9_4;;
-    CT_CC_GCC_V_5_4_0)              replace CT_GCC_V_5_5_0;;
-    CT_CC_GCC_V_6_3_0)              replace CT_GCC_V_6_5_0;;
-    CT_CC_GCC_V_linaro_4_8)         select_linaro GCC; replace CT_GCC_LINARO_V_4_8_2015_06;;
-    CT_CC_GCC_V_linaro_4_9)         select_linaro GCC; replace CT_GCC_LINARO_V_4_9_2017_01;;
-    CT_CC_GCC_V_linaro_5_4)         select_linaro GCC; replace CT_GCC_LINARO_V_5_5_2017_10;;
-    CT_CC_GCC_V_linaro_6_3)         select_linaro GCC; replace CT_GCC_LINARO_V_6_4_2018_05;;
-    CT_CLOOG_V_0_18_0)              replace CT_CLOOG_V_0_18_1;;
-    CT_CLOOG_V_0_18_1)              replacement_for CT_CLOOG_V_0_18_0;;
-    CT_EXPAT_V_2_2_0)               replace CT_EXPAT_V_2_2_6;; # 2.2.6 was not available in ct-ng 1.23.0 - no replacement_for
-    CT_GDB_V_6_8a)                  replace CT_GDB_V_6_8A;;
-    CT_GDB_V_7_0a)                  replace CT_GDB_V_7_0_1A;;
-    CT_GDB_V_7_0_1a)                replace CT_GDB_V_7_0_1A;;
-    CT_GDB_V_7_1a)                  replace CT_GDB_V_7_1A;;
-    CT_GDB_V_7_2a)                  replace CT_GDB_V_7_2A;;
-    CT_GDB_V_7_3a)                  replace CT_GDB_V_7_3A;;
-    CT_GDB_V_7_4)                   replace CT_GDB_V_7_4_1;;
-    CT_GDB_V_7_7)                   replace CT_GDB_V_7_7_1;;
-    CT_GDB_V_7_8|CT_GDB_V_7_8_1)    replace CT_GDB_V_7_8_2;;
-    CT_GDB_V_7_8_2)                 replacement_for CT_GDB_V_7_8 CT_GDB_V_7_8_1;;
-    CT_GDB_V_7_9)                   replace CT_GDB_V_7_9_1;;
-    CT_GDB_V_7_10)                  replace CT_GDB_V_7_10_1;;
-    CT_GDB_V_linaro_7_3)            select_linaro GDB; replace CT_GDB_LINARO_V_7_3_2011_12;;
-    CT_GDB_V_linaro_7_4)            select_linaro GDB; replace CT_GDB_LINARO_V_7_4_2012_06;;
-    CT_GDB_V_linaro_7_5)            select_linaro GDB; replace CT_GDB_LINARO_V_7_5_2012_12;;
-    CT_GDB_V_linaro_7_6)            select_linaro GDB; replace CT_GDB_LINARO_V_7_6_1_2013_10;;
-    CT_GDB_V_linaro_7_7)            select_linaro GDB; replace CT_GDB_LINARO_V_7_7_1_2014_06_1;;
-    CT_GDB_V_linaro_7_7_1)          select_linaro GDB; replace CT_GDB_LINARO_V_7_7_1_2014_06_1;;
-    CT_GDB_V_linaro_7_8)            select_linaro GDB; replace CT_GDB_LINARO_V_7_8_2014_09;;
-    CT_GMP_V_4_3_0|CT_GMP_V_4_3_1)  replace CT_GMP_V_4_3_2;;
-    CT_GMP_V_4_3_2)                 replacement_for CT_GMP_V_4_3_0 CT_GMP_V_4_3_1;;
-    CT_GMP_V_5_0_1|CT_GMP_V_5_0_2)  replace CT_GMP_V_5_0_5;; # 5.0.5 not in ct-ng 1.23.0
-    CT_GMP_V_5_1_1)                 replace CT_GMP_V_5_1_3;;
-    CT_GMP_V_5_1_3)                 replacement_for CT_GMP_V_5_1_1;;
-    CT_GMP_V_6_0_0)                 replace CT_GMP_V_6_0_0A;; # 6.0.0a not in ct-ng 1.23.0
-    CT_GMP_V_6_1_0)                 replace CT_GMP_V_6_1_2;;
-    CT_GMP_V_6_1_2)                 replacement_for CT_GMP_V_6_1_0;;
-    CT_ISL_V_0_11_1)                replace CT_ISL_V_0_11_2;;
-    CT_ISL_V_0_14)                  replace CT_ISL_V_0_14_1;;
-    CT_KERNEL_V_2_6_32|CT_KERNEL_V_2_6_33|CT_KERNEL_V_2_6_34|CT_KERNEL_V_2_6_35|\
-    CT_KERNEL_V_2_6_36|CT_KERNEL_V_2_6_37|CT_KERNEL_V_2_6_38|CT_KERNEL_V_2_6_39|\
-    CT_KERNEL_V_3_0|CT_KERNEL_V_3_1|CT_KERNEL_V_3_2|CT_KERNEL_V_3_3|CT_KERNEL_V_3_4|CT_KERNEL_V_3_5|\
-    CT_KERNEL_V_3_6|CT_KERNEL_V_3_7|CT_KERNEL_V_3_8|CT_KERNEL_V_3_9|CT_KERNEL_V_3_10|CT_KERNEL_V_3_11|\
-    CT_KERNEL_V_3_12|CT_KERNEL_V_3_13|CT_KERNEL_V_3_14|CT_KERNEL_V_3_15|CT_KERNEL_V_3_16|\
-    CT_KERNEL_V_3_17|CT_KERNEL_V_3_18|CT_KERNEL_V_3_19|\
-    CT_KERNEL_V_4_0|CT_KERNEL_V_4_1|CT_KERNEL_V_4_2|CT_KERNEL_V_4_3|CT_KERNEL_V_4_4|\
-    CT_KERNEL_V_4_5|CT_KERNEL_V_4_6|CT_KERNEL_V_4_7|CT_KERNEL_V_4_8|CT_KERNEL_V_4_9|CT_KERNEL_V_4_10)
-                                    replace CT_LINUX_${opt#CT_KERNEL_};;
-    CT_LIBC_AVR_LIBC_V_1_8_0)       replace CT_AVR_LIBC_V_1_8_1;;
-    CT_LIBC_AVR_LIBC_V_1_8_1)       replace CT_AVR_LIBC_V_1_8_1;;
-    CT_LIBC_AVR_LIBC_V_2_0_0)       replace CT_AVR_LIBC_V_2_0_0;;
-    CT_LIBC_GLIBC_V_2_12_1|CT_LIBC_GLIBC_V_2_12_2|CT_LIBC_GLIBC_V_2_13|CT_LIBC_GLIBC_V_2_14|\
-    CT_LIBC_GLIBC_V_2_14_1|CT_LIBC_GLIBC_V_2_15|CT_LIBC_GLIBC_V_2_16_0|CT_LIBC_GLIBC_V_2_17|\
-    CT_LIBC_GLIBC_V_2_18|CT_LIBC_GLIBC_V_2_19|CT_LIBC_GLIBC_V_2_20|CT_LIBC_GLIBC_V_2_21|\
-    CT_LIBC_GLIBC_V_2_22|CT_LIBC_GLIBC_V_2_23|CT_LIBC_GLIBC_V_2_24|CT_LIBC_GLIBC_V_2_25)
-                                    replace CT_GLIBC_${opt#CT_LIBC_GLIBC_};;
-    CT_LIBC_GLIBC_LINARO_V_2_20)    replace CT_GLIBC_LINARO_V_2_20_2014_11;;
-    CT_LIBC_MUSL_V_1_1_15|CT_LIBC_MUSL_V_1_1_16)
-                                    replace CT_MUSL_${opt#CT_LIBC_MUSL_};;
-    CT_LIBC_NEWLIB_V_1_17_0|CT_LIBC_NEWLIB_V_1_18_0|CT_LIBC_NEWLIB_V_1_19_0|CT_LIBC_NEWLIB_V_1_20_0|\
-    CT_LIBC_NEWLIB_V_2_0_0|CT_LIBC_NEWLIB_V_2_1_0|CT_LIBC_NEWLIB_V_2_2_0|CT_LIBC_NEWLIB_V_2_3_0|\
-    CT_LIBC_NEWLIB_V_2_4_0|CT_LIBC_NEWLIB_V_2_5_0)
-                                    replace CT_NEWLIB_${opt#CT_LIBC_NEWLIB_};;
-    CT_LIBC_NEWLIB_LINARO_V_2_1_0)  select_linaro NEWLIB; replace CT_NEWLIB_LINARO_V_2_1_0_2014;;
-    CT_LIBC_NEWLIB_LINARO_V_2_2_0)  select_linaro NEWLIB; replace CT_NEWLIB_LINARO_V_2_2_0_2015;;
-    CT_LIBELF_V_0_8_12)             replace CT_LIBELF_V_0_8_13;;
-    CT_LIBELF_V_0_8_13)             replacement_for CT_LIBELF_V_0_8_12;;
-    CT_M4_V_1_4_13|CT_M4_V_1_4_17)  replace CT_M4_V_1_4_18;;
-    CT_M4_V_1_4_18)                 replacement_for CT_M4_V_1_4_13 CT_M4_V_1_4_17;;
-    CT_MPC_V_0_8_1)                 replace CT_MPC_V_0_8_2;;
-    CT_MPC_V_0_8_2)                 replacement_for CT_MPC_V_0_8_1;;
-    CT_MPC_V_1_0|CT_MPC_V_1_0_1|CT_MPC_V_1_0_2)
-                                    replace CT_MPC_V_1_0_3;;
-    CT_MPC_V_1_0_3)                 replacement_for CT_MPC_V_1_0 CT_MPC_V_1_0_1 CT_MPC_V_1_0_2;;
-    CT_MPFR_V_2_4_0|CT_MPFR_V_2_4_1)
-                                    replace CT_MPFR_V_2_4_2;;
-    CT_MPFR_V_2_4_2)                replacement_for CT_MPFR_V_2_4_0 CT_MPFR_V_2_4_1;;
-    CT_MPFR_V_3_0_0)                replace CT_MPFR_V_3_0_1;;
-    CT_MPFR_V_3_0_1)                replacement_for CT_MPFR_V_3_0_0;;
-    CT_MPFR_V_3_1_0|CT_MPFR_V_3_1_2|CT_MPFR_V_3_1_3|CT_MPFR_V_3_1_5)
-                                    replace CT_MPFR_V_3_1_6;;
-    CT_MPFR_V_3_1_6)                replacement_for CT_MPFR_V_3_1_0 CT_MPFR_V_3_1_2 CT_MPFR_V_3_1_3 CT_MPFR_V_3_1_5;;
-    CT_STRACE_V_4_5_18|CT_STRACE_V_4_5_19)
-                                    replace CT_STRACE_V_4_5_20;;
-    CT_STRACE_V_4_5_20)             replacement_for CT_STRACE_V_4_5_18 CT_STRACE_V_4_5_19;;
-    CT_LIBC_UCLIBC_NG_V_1_0_20|CT_LIBC_UCLIBC_NG_V_1_0_21|CT_LIBC_UCLIBC_NG_V_1_0_22)
-                                    if is_set; then
-                                        echo "CT_UCLIBC_USE_UCLIBC_NG_ORG=y"
-                                    fi
-                                    replace CT_UCLIBC_NG_V_1_0_25
-                                    ;;
-    CT_LIBC_UCLIBC_V_0_9_33_2)
-                                    if is_set; then
-                                        echo "CT_UCLIBC_USE_UCLIBC_ORG=y"
-                                    fi
-                                    replace CT_UCLIBC_V_0_9_33_2
-                                    ;;
-    CT_WINAPI_V_2_0_7|CT_WINAPI_V_2_0_7|CT_WINAPI_V_2_0_9)
-                                    replace CT_MINGW_W64_V_V2_0_10;;
-    CT_WINAPI_V_3_0_0)              replace CT_MINGW_W64_V_V3_0_0;;
-    CT_WINAPI_V_3_1_0)              replace CT_MINGW_W64_V_V3_1_0;;
-    CT_WINAPI_V_3_2_0)              replace CT_MINGW_W64_V_V3_2_0;;
-    CT_WINAPI_V_3_3_0)              replace CT_MINGW_W64_V_V3_3_0;;
-    CT_WINAPI_V_4_0_0|CT_WINAPI_V_4_0_1|CT_WINAPI_V_4_0_2|CT_WINAPI_V_4_0_3|\
-    CT_WINAPI_V_4_0_4|CT_WINAPI_V_4_0_5|CT_WINAPI_V_4_0_6)
-                                    replace CT_MINGW_W64_V_V4_0_6;;
-    CT_WINAPI_V_5_0_0|CT_WINAPI_V_5_0_1)
-                                    replace CT_MINGW_W64_V_V5_0_3;;
-
-    # Misc
-    CT_CLOOG_NEEDS_AUTORECONF)
-        # Was unused in 1.23, just drop
-        unset opt
-        ;;
-    CT_PATCH_SINGLE)
-        # Internal selector in 1.23
-        unset opt
-        ;;
-    CT_PATCH_BUNDLED_FALLBACK_LOCAL|CT_PATCH_LOCAL_FALLBACK_BUNDLED)
-        warning_if_set "Fallback patch order has been removed"
-        ;;
-    CT_CC_GCC_TARGET_FINAL)
-        warning_if_set "Option removed"
-        ;;
-    CT_COMPLIBS|CT_COMPLIBS_NEEDED|CT_CC_GCC_latest)
-        # Internal selectors
-        unset opt
-        ;;
+    case "${ln}" in
+        CT_*=*)
+            opt=${ln%%=*}
+            val=${ln#*=}
+            case "${val}" in
+            \"*\")
+                val="${val%\"}"
+                val="${val#\"}"
+                q=\"
+                ;;
+            esac
+            return 0
+            ;;
+        "# CT_"*" is not set")
+            opt=${ln#* }
+            opt=${opt%% *}
+            return 0
+            ;;
+        *)
+            ;;
     esac
+    return 1
 }
 
-# Upgrade v1 -> v2: several packages had their config options renamed
-# to leave only the relevant part - so that further upgrades of, say,
-# GCC 6.5.0 to 6.6.0 do not result in config changes.
-upgrade_v1()
-{
-    case "${opt}" in
-    CT_ANDROID_NDK_V_R10E|CT_ANDROID_NDK_V_R11C|CT_ANDROID_NDK_V_R12B|\
-    CT_ANDROID_NDK_V_R13B|CT_ANDROID_NDK_V_R14B|CT_ANDROID_NDK_V_R15C|\
-    CT_ANDROID_NDK_V_R16B|CT_ANDROID_NDK_V_R17C)
-        replace "${opt%[A-Z]}"
-        ;;
-    CT_AUTOMAKE_V_1_11_6|CT_AUTOMAKE_V_1_14_1|\
-    CT_AUTOMAKE_V_1_15_1|CT_AUTOMAKE_V_1_16_1)
-        replace "${opt%_[0-9]}"
-        ;;
-    CT_BINUTILS_LINARO_V_2_23_2_2013_10_4|CT_BINUTILS_LINARO_V_2_24_0_2014_11_2|\
-    CT_BINUTILS_LINARO_V_2_25_0_2015_01_2)
-        replace "${opt%_[0-9]_201[345]*}"
-        ;;
-    CT_BINUTILS_V_2_23_2|CT_BINUTILS_V_2_25_1|CT_BINUTILS_V_2_26_1|\
-    CT_BINUTILS_V_2_28_1|CT_BINUTILS_V_2_29_1|CT_BINUTILS_V_2_31_1)
-        replace "${opt%_[0-9]}"
-        ;;
-    CT_DTC_V_1_4_7)
-        replace CT_DTC_V_1_4
-        ;;
-    CT_EXPAT_V_2_1_1|CT_EXPAT_V_2_2_6)
-        replace "${opt%_[0-9]}"
-        ;;
-    CT_GCC_LINARO_V_4_8_2015_06|CT_GCC_LINARO_V_4_9_2017_01)
-        replace "${opt%_201[57]*}"
-        ;;
-    CT_GCC_LINARO_V_5_5_2017_10|CT_GCC_LINARO_V_6_4_2018_05|\
-    CT_GCC_LINARO_V_7_3_2018_05)
-        replace "${opt%_[0-9]_201[78]*}"
-        ;;
-    CT_GCC_V_4_8_5|CT_GCC_V_4_9_4)
-        replace "${opt%_[0-9]}"
-        ;;
-    CT_GCC_V_5_5_0|CT_GCC_V_6_5_0|CT_GCC_V_7_4_0|CT_GCC_V_8_2_0)
-        replace "${opt%_[0-9]_[0-9]}"
-        ;;
-    CT_GDB_LINARO_V_7_3_2011_12|CT_GDB_LINARO_V_7_4_2012_06|CT_GDB_LINARO_V_7_5_2012_12|\
-    CT_GDB_LINARO_V_7_7_2014_05|CT_GDB_LINARO_V_7_8_2014_09)
-        replace "${opt%_201[57]*}"
-        ;;
-    CT_GDB_LINARO_V_7_6_1_2013_10|CT_GDB_LINARO_V_7_7_1_2014_06_1)
-        replace "${opt%_[0-9]_201[345]*}"
-        ;;
-
-    CT_GDB_V_6_8A|CT_GDB_V_7_1A|CT_GDB_V_7_2A)
-        replace "${opt%A}"
-        ;;
-    CT_GDB_V_7_0_1A)
-        replace CT_GDB_V_7_0
-        ;;
-    CT_GDB_V_7_3_1|CT_GDB_V_7_4_1|CT_GDB_V_7_5_1|CT_GDB_V_7_6_1|CT_GDB_V_7_7_1|\
-    CT_GDB_V_7_8_2|CT_GDB_V_7_9_1|CT_GDB_V_7_10_1|CT_GDB_V_7_11_1|CT_GDB_V_7_12_1|\
-    CT_GDB_V_8_0_1|CT_GDB_V_8_1_1)
-        replace "${opt%_[0-9]}"
-        ;;
-    CT_GLIBC_LINARO_V_2_20_2014_11)
-        replace CT_GLIBC_LINARO_V_2_20
-        ;;
-    CT_GMP_V_4_3_2|CT_GMP_V_5_0_5|CT_GMP_V_5_1_3|CT_GMP_V_6_0_0A|CT_GMP_V_6_1_2)
-        replace "${opt%_[0-9]*}"
-        ;;
-    CT_ISL_V_0_11_2|CT_ISL_V_0_12_2|CT_ISL_V_0_14_1|CT_ISL_V_0_16_1|CT_ISL_V_0_17_1)
-        replace "${opt%_[0-9]}"
-        ;;
-    CT_LIBELF_V_0_8_13)
-        replace CT_LIBELF_V_0_8
-        ;;
-    CT_LIBTOOL_V_2_4_6)
-        replace CT_LIBTOOL_V_2_4
-        ;;
-    CT_M4_V_1_4_18)
-        replace CT_M4_V_1_4
-        ;;
-    CT_MAKE_V_4_2_1)
-        replace CT_MAKE_V_4_2
-        ;;
-    CT_MINGW_W64_V_V2_0_10|CT_MINGW_W64_V_V3_0_0|CT_MINGW_W64_V_V3_1_0|CT_MINGW_W64_V_V3_2_0|\
-    CT_MINGW_W64_V_V3_3_0|CT_MINGW_W64_V_V4_0_6|CT_MINGW_W64_V_V5_0_3|CT_MINGW_W64_V_V6_0_0)
-        replace "${opt%_[0-9]}"
-        ;;
-    CT_MPC_V_0_8_2|CT_MPC_V_1_0_3|CT_MPC_V_1_1_0)
-        replace "${opt%_[0-9]}"
-        ;;
-    CT_MPFR_V_2_4_2|CT_MPFR_V_3_0_1|CT_MPFR_V_3_1_6|CT_MPFR_V_4_0_1)
-        replace "${opt%_[0-9]}"
-        ;;
-    CT_NEWLIB_LINARO_V_2_1_0_2014|CT_NEWLIB_LINARO_V_2_2_0_2015)
-        replace "${opt%_[0-9]_201[345]*}"
-        ;;
-    CT_NEWLIB_V_1_17_0|CT_NEWLIB_V_1_18_0|CT_NEWLIB_V_1_19_0|CT_NEWLIB_V_1_20_0|CT_NEWLIB_V_2_0_0|\
-    CT_NEWLIB_V_2_1_0|CT_NEWLIB_V_2_2_0|CT_NEWLIB_V_2_3_0|CT_NEWLIB_V_2_4_0|CT_NEWLIB_V_2_5_0|\
-    CT_NEWLIB_V_3_0_0)
-        replace "${opt%_[0-9]}"
-        ;;
-
-    CT_CLOOG_HAS_WITH_GMP_ISL_OSL|CT_CLOOG_0_18_or_later|CT_CLOOG_0_18_or_older|\
-    CT_CLOOG_REQUIRE_0_18_or_later|CT_CLOOG_REQUIRE_0_18_or_older|\
-    CT_CLOOG_REQUIRE_later_than_0_18|CT_CLOOG_REQUIRE_older_than_0_18|\
-    CT_CLOOG_later_than_0_18|CT_CLOOG_older_than_0_18|CT_GCC_REQUIRE_4_9_2_or_later|\
-    CT_GCC_REQUIRE_4_9_2_or_older|CT_GCC_REQUIRE_later_than_4_9_2|\
-    CT_GCC_REQUIRE_older_than_4_9_2|CT_GCC_4_9_2_or_later|CT_GCC_4_9_2_or_older|\
-    CT_GCC_BUG_61144|CT_GCC_later_than_4_9_2|CT_GCC_older_than_4_9_2)
-        unset opt # No longer used auto-selectors
-        ;;
-    esac
-}
 
 # Main upgrade driver. One version at a time, read line by line, interpret
 # the options and replace anything that needs replacing.
 cp "${CFGFILE}" "${CFGFILE}.before-upgrade"
-v=${CT_CONFIG_VERSION}
 input="${CFGFILE}"
-while [ "${v}" -lt "${CT_CONFIG_VERSION_CURRENT}" ]; do
+while :; do
+    # Purge any possibly stale values
+    unset "${!CT_@}"
+    # Reload the next input so that the upgrade function can rely on other CT_xxx variables,
+    # not just the currently processed variable.
+    . "${input}"
+    v=${CT_CONFIG_VERSION:-0}
+    if [ "${v}" -ge "${MY_CONFIG_VERSION_CURRENT}" ]; then
+        break
+    fi
+
     vn=$[ v + 1 ]
     info "Upgrading v${v} to v${vn}"
+    if [ ! -r "${MY_LIB_DIR}/scripts/upgrade/v${v}" ]; then
+        error "Missing upgrade script for v${v} of the config file"
+    fi
+    unset upgrade
+    . "${MY_LIB_DIR}/scripts/upgrade/v${v}"
+    # First pass: read in the whole file and mark the options mentioned;
+    # it may not be possible to upgrade a defconfig if some non-trivial
+    # option dependencies need to be resolved. We are not interested in
+    # values yet.
+    unset selected_opts
+    declare -A selected_opts
+    while read ln; do
+        if set_opt_and_val; then
+            selected_opts[${opt}]=1
+        fi
+    done < "${input}"
+
+    # Second pass: actually upgrade the options.
     {
         while read ln; do
+            unset opt
             unset val
             q=
-            case "${ln}" in
-                CT_CONFIG_VERSION_CURRENT=*|CT_CONFIG_VERSION=*)
-                    continue
-                    ;;
-                CT_*=*)
-                    opt=${ln%%=*}
-                    val=${ln#*=}
-                    case "${val}" in
-                    \"*\")
-                        val="${val%\"}"
-                        val="${val#\"}"
-                        q=\"
+            if set_opt_and_val; then
+                case "${opt}" in
+                    CT_CONFIG_VERSION_CURRENT=*|CT_CONFIG_VERSION=*)
+                        continue
                         ;;
-                    esac
-                    ;;
-                "# CT_"*" is not set")
-                    opt=${ln#* }
-                    opt=${opt%% *}
-                    ;;
-                *)
-                    echo "${ln}"
-                    continue
-                    ;;
-            esac
-            upgrade_v${v}
+                esac
+            else
+                echo "${ln}"
+            fi
+            upgrade
             # Emit the option(s)
             if [ x${opt+set} = x ]; then
                 continue
@@ -616,10 +205,6 @@ while [ "${v}" -lt "${CT_CONFIG_VERSION_CURRENT}" ]; do
     v=${vn}
     rm -f "${input}"
     input="${CFGFILE}.${vn}"
-    # Reload the next input so that the upgrade function can rely on other CT_xxx variables,
-    # not just the currently processed variable.
-    # TBD clean the environment first to avoid any stale values
-    . "${input}"
     # Ideally, we'd do 'ct-ng olddefconfig' after each step with the appropriate
     # Kconfig so that the next step would be able to use auto-set values from the
     # previous step. However, that would require us to keep archived config/ trees
@@ -627,7 +212,7 @@ while [ "${v}" -lt "${CT_CONFIG_VERSION_CURRENT}" ]; do
     # this until it is actually needed. Even then, it is probably sufficient to only
     # keep the versions where there is such a dependency.
 done
-mv "${CFGFILE}.${CT_CONFIG_VERSION_CURRENT}" "${CFGFILE}"
+mv "${CFGFILE}.${MY_CONFIG_VERSION_CURRENT}" "${CFGFILE}"
 cp "${CFGFILE}" "${CFGFILE}.before-olddefconfig"
 cat >&2 <<EOF