kbuild: enable 'make CFLAGS=...' to add additional options to CC

The variable CFLAGS is a wellknown variable and the usage by
kbuild may result in unexpected behaviour.
On top of that several people over time has asked for a way to
pass in additional flags to gcc.

This patch replace use of CFLAGS with KBUILD_CFLAGS all over the
tree and enabling one to use:
make CFLAGS=...
to specify additional gcc commandline options.

One usecase is when trying to find gcc bugs but other
use cases has been requested too.

Patch was tested on following architectures:
alpha, arm, i386, x86_64, mips, sparc, sparc64, ia64, m68k

Test was simple to do a defconfig build, apply the patch and check
that nothing got rebuild.

Signed-off-by: Sam Ravnborg <sam@ravnborg.org>

1 files changed, 4 insertions, 4 deletions

diff --git a/arch/m68k/Makefile b/arch/m68k/Makefile
index aa383a5ea7a..4a1bd44ff16 100644
--- a/arch/m68k/Makefile
+++ b/arch/m68k/Makefile
@@ -32,18 +32,18 @@ endif
 CHECKFLAGS += -D__mc68000__
 
 # without -fno-strength-reduce the 53c7xx.c driver fails ;-(
-CFLAGS += -pipe -fno-strength-reduce -ffixed-a2
+KBUILD_CFLAGS += -pipe -fno-strength-reduce -ffixed-a2
 
 # enable processor switch if compiled only for a single cpu
 ifndef CONFIG_M68020
 ifndef CONFIG_M68030
 
 ifndef CONFIG_M68060
-CFLAGS := $(CFLAGS) -m68040
+KBUILD_CFLAGS += -m68040
 endif
 
 ifndef CONFIG_M68040
-CFLAGS := $(CFLAGS) -m68060
+KBUILD_CFLAGS += -m68060
 endif
 
 endif
@@ -52,7 +52,7 @@ endif
 ifdef CONFIG_KGDB
 # If configured for kgdb support, include debugging infos and keep the
 # frame pointer
-CFLAGS := $(subst -fomit-frame-pointer,,$(CFLAGS)) -g
+KBUILD_CFLAGS := $(subst -fomit-frame-pointer,,$(KBUILD_CFLAGS)) -g
 endif
 
 ifndef CONFIG_SUN3