config: add an option not to remove the destination directory

In certain circumstances, removing the destination/installation directory
is a bad idea. For example, when the build environment is already taking
care of sanitising the build tree, and pre-installs stuff in there, it is
a very bad idea to remove the destination directory.

This happens now in buildroot, as the crostool-NG backend now installs the
toolchain in the common host-tools directory, and pre-install there a few
host-utilities (eg. host-automake and host-gawk).

Provide a config knob to turn on/off the removal of the destination
directory, defaulting to 'y' (previous behavior), and forced to 'n' when
used as a backend.

Reported-by: Peter Korsgaard <jacmet@sunsite.dk>
Signed-off-by: "Yann E. MORIN" <yann.morin.1998@anciens.enib.fr>

2 files changed, 23 insertions, 1 deletions

diff --git a/config/global/paths.in b/config/global/paths.in
index 341d207..b97e258 100644
--- a/config/global/paths.in
+++ b/config/global/paths.in
@@ -61,6 +61,28 @@ config INSTALL_DIR
 #      The reason you might also want to install elsewhere is if you are going
 #      to package your shinny new toolchain for distribution.
 
+config RM_RF_PREFIX_DIR
+    bool
+    prompt "|  Remove the prefix dir prior to building"
+    default y
+    depends on !BACKEND
+    help
+      If you say 'y' here, then PREFIX_DIR (above) will be eradicated
+      prior to the toolchain is built.
+      
+      This can be usefull when you are trying different settings (due
+      to build failures or feature tests). In this case, to avoid using
+      a potentially broken previous toolchain, the install location is
+      removed, to start afresh.
+      
+      On the oher hand, if you are building a final toolchain, and install
+      it into a directory with pre-install, unrelated programs, it would be
+      damageable to remove that directory. In this case, you may want to
+      say 'n' here.
+      
+      Note that when acting as a backend, this option is not available, and
+      is forced to 'n'.
+
 config REMOVE_DOCS
     bool
     prompt "Remove documentation"
diff --git a/scripts/crosstool-NG.sh.in b/scripts/crosstool-NG.sh.in
index 2fa1994..fffb841 100644
--- a/scripts/crosstool-NG.sh.in
+++ b/scripts/crosstool-NG.sh.in
@@ -229,7 +229,7 @@ if [ -z "${CT_RESTART}" ]; then
     if [ "${CT_FORCE_EXTRACT}" = "y" -a -d "${CT_SRC_DIR}" ]; then
         CT_DoForceRmdir "${CT_SRC_DIR}"
     fi
-    if [ -d "${CT_INSTALL_DIR}" ]; then
+    if [ -d "${CT_INSTALL_DIR}" -a "${CT_RM_RF_PREFIX_DIR}" = "y" ]; then
         CT_DoForceRmdir "${CT_INSTALL_DIR}"
     fi
     # In case we start anew, get rid of the previously saved state directory