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, 2 insertions, 2 deletions

diff --git a/arch/sh/Makefile b/arch/sh/Makefile
index 97ac58682d0f..cd8a411acc95 100644
--- a/arch/sh/Makefile
+++ b/arch/sh/Makefile
@@ -91,12 +91,12 @@ LDFLAGS_vmlinux		+= --defsym 'jiffies=jiffies_64+4'
 LDFLAGS                 += -EB
 endif
 
-CFLAGS          += -pipe $(cflags-y)
+KBUILD_CFLAGS           += -pipe $(cflags-y)
 AFLAGS          += $(cflags-y)
 
 head-y := arch/sh/kernel/head.o arch/sh/kernel/init_task.o
 
-LIBGCC := $(shell $(CC) $(CFLAGS) -print-libgcc-file-name)
+LIBGCC := $(shell $(CC) $(KBUILD_CFLAGS) -print-libgcc-file-name)
 
 core-y                          += arch/sh/kernel/ arch/sh/mm/
 core-$(CONFIG_SH_FPU_EMU)       += arch/sh/math-emu/