[PATCH] Avoid rebuilding everything if user changes CFLAGS on the make command line

[Johannes Sixt <J.Sixt@eudaptics.com>]

From: Johannes Sixt <johannes.sixt@telecom.at>

The following sequence of commands is commonly used to recompile
selected files with different flags, for example, to change the debug
information:

   make
   rm builtin-diff.o
   make CFLAGS="-g -O0"

However, the Makefile is clever enough to notice that the second 'make'
invocation changes the build flags and rebuilds everything.

This change exempts the value of CFLAGS (which is explicitly declared
as reserved for the user to change from the command line) from this
auto-detection.

Signed-off-by: Johannes Sixt <johannes.sixt@telecom.at>
---
Johannes Schindelin wrote:
>  GIT-CFLAGS: .FORCE-GIT-CFLAGS
>         @FLAGS='$(TRACK_CFLAGS)'; \
> -           if test x"$$FLAGS" != x"`cat GIT-CFLAGS 2>/dev/null`" ; then \
> +           if test x"$$FLAGS" != x"`cat GIT-CFLAGS 2>/dev/null`" -a \
> +                   -z "$(IGNORE_GIT_CFLAGS)"; then \
>                 echo 1>&2 "    * new build flags or prefix"; \
>                 echo "$$FLAGS" >GIT-CFLAGS; \
>              fi

IMHO, the value of $(CFLAGS) (which the Makefile declares as "for the
users to override from the command line") should never take part in this
build-flags-change-autodetection.

-- Hannes

 Makefile |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/Makefile b/Makefile
index 9a37b15..8410530 100644
--- a/Makefile
+++ b/Makefile
@@ -812,7 +812,7 @@ tags:
 	find . -name '*.[hcS]' -print | xargs ctags -a
 
 ### Detect prefix changes
-TRACK_CFLAGS = $(subst ','\'',$(ALL_CFLAGS)):\
+TRACK_CFLAGS = $(subst ','\'',$(BASIC_CFLAGS)):\
             
$(bindir_SQ):$(gitexecdir_SQ):$(template_dir_SQ):$(prefix_SQ)
 
 GIT-CFLAGS: .FORCE-GIT-CFLAGS
-- 
1.5.0.2.279.g4808