From 37ac0e8474883ce9202ef4e08b7d9f9f66ea8a5d Mon Sep 17 00:00:00 2001
From: Alexey Neyman <stilor@att.net>
Date: Mon, 14 May 2018 23:47:17 -0700
Subject: Too many fixes need backporting for GCC8...

... so instead, disable -Werror for older versions of glibc.

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

diff --git a/config/libc/glibc.in b/config/libc/glibc.in
index 00fffa7..5916a83 100644
--- a/config/libc/glibc.in
+++ b/config/libc/glibc.in
@@ -112,12 +112,6 @@ config GLIBC_HAS_OBSOLETE_RPC
     def_bool y
     depends on GLIBC_2_14_or_later
 
-# New GCC versions don't like the ifunc implementation in GCC, producing a warning.
-# We can either require old GCC for those versions, or disable erroring out on warnings.
-config GLIBC_HAS_NEW_IFUNC
-    def_bool y
-    depends on GLIBC_2_25_or_later
-
 config GLIBC_EXTRA_CONFIG_ARRAY
     string
     prompt "extra config"
@@ -326,4 +320,16 @@ config GLIBC_MIN_KERNEL
     default LINUX_VERSION                 if GLIBC_KERNEL_VERSION_AS_HEADERS
     default GLIBC_MIN_KERNEL_VERSION      if GLIBC_KERNEL_VERSION_CHOSEN
 
+# All supported versions of glibc build cleanly with GCC7 and earlier.
+# GCC8-related fixes were only available in glibc 2.27.
+config GLIBC_ENABLE_WERROR
+    bool "Enable -Werror during the build"
+    default y if GCC_7_or_older
+    default y if GCC_8_or_later && GLIBC_2_27_or_later
+    help
+      By default, glibc enables strict warning checks during the build.
+      However, older version of glibc may not build with newer versions
+      of the compiler than there were available at the time of a glibc
+      release (because newer compilers typically have better diagnostics).
+
 endif # KERNEL_LINUX
diff --git a/packages/glibc/package.desc b/packages/glibc/package.desc
index 158e637..ea03e69 100644
--- a/packages/glibc/package.desc
+++ b/packages/glibc/package.desc
@@ -1,6 +1,6 @@
 origin='GNU'
 repository='git git://sourceware.org/git/glibc.git'
 mirrors='$(CT_Mirrors GNU glibc)'
-milestones='2.14 2.17 2.20 2.23 2.24 2.25 2.26'
+milestones='2.14 2.17 2.20 2.23 2.24 2.26 2.27'
 archive_formats='.tar.xz .tar.bz2 .tar.gz'
 signature_format='packed/.sig'
diff --git a/scripts/build/libc/glibc.sh b/scripts/build/libc/glibc.sh
index 4b1c688..2f257b5 100644
--- a/scripts/build/libc/glibc.sh
+++ b/scripts/build/libc/glibc.sh
@@ -171,6 +171,7 @@ do_libc_backend_once() {
         *)  extra_config+=("--enable-add-ons=$(do_libc_add_ons_list ,)");;
     esac
 
+    [ "${CT_GLIBC_ENABLE_WERROR}" != "y" ] && extra_config+=("--disable-werror")
     [ -n "${CT_PKGVERSION}" ] && extra_config+=("--with-pkgversion=${CT_PKGVERSION}")
     [ -n "${CT_TOOLCHAIN_BUGURL}" ] && extra_config+=("--with-bugurl=${CT_TOOLCHAIN_BUGURL}")
 
@@ -200,13 +201,6 @@ do_libc_backend_once() {
     glibc_cflags+=" ${CT_GLIBC_EXTRA_CFLAGS}"
     glibc_cflags+=" ${multi_flags}"
 
-    # Before 2.25, glibc didn't use GCC's ifunc attribute, instead creating
-    # the resolvers through some clever assembly. This had the resolver function
-    # aliased with an incompatible type, and GCC8 now complains about it.
-    if [ "${CT_GLIBC_HAS_NEW_IFUNC}" != "y" ]; then
-        glibc_cflags+=" -Wno-error=attribute-alias"
-    fi
-
     # Analyze the resulting options for any extra configure switches to throw in.
     for opt in ${glibc_cflags}; do
         case ${opt} in
-- 
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