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>

2 files changed, 5 insertions, 5 deletions

diff --git a/arch/arm/Makefile b/arch/arm/Makefile
index fa4ea9ff0797..0b82865ab506 100644
--- a/arch/arm/Makefile
+++ b/arch/arm/Makefile
@@ -14,9 +14,9 @@ LDFLAGS_vmlinux	:=-p --no-undefined -X
 CPPFLAGS_vmlinux.lds = -DTEXT_OFFSET=$(TEXT_OFFSET)
 OBJCOPYFLAGS    :=-O binary -R .note -R .comment -S
 GZFLAGS         :=-9
-#CFLAGS         +=-pipe
+#KBUILD_CFLAGS  +=-pipe
 # Explicitly specifiy 32-bit ARM ISA since toolchain default can be -mthumb:
-CFLAGS          +=$(call cc-option,-marm,)
+KBUILD_CFLAGS   +=$(call cc-option,-marm,)
 
 # Do not use arch/arm/defconfig - it's always outdated.
 # Select a platform tht is kept up-to-date
@@ -28,7 +28,7 @@ MMUEXT		:= -nommu
 endif
 
 ifeq ($(CONFIG_FRAME_POINTER),y)
-CFLAGS          +=-fno-omit-frame-pointer -mapcs -mno-sched-prolog
+KBUILD_CFLAGS   +=-fno-omit-frame-pointer -mapcs -mno-sched-prolog
 endif
 
 ifeq ($(CONFIG_CPU_BIG_ENDIAN),y)
@@ -85,7 +85,7 @@ CFLAGS_ABI	:=$(call cc-option,-mapcs-32,-mabi=apcs-gnu) $(call cc-option,-mno-th
 endif
 
 # Need -Uarm for gcc < 3.x
-CFLAGS          +=$(CFLAGS_ABI) $(arch-y) $(tune-y) $(call cc-option,-mshort-load-bytes,$(call cc-option,-malignment-traps,)) -msoft-float -Uarm
+KBUILD_CFLAGS   +=$(CFLAGS_ABI) $(arch-y) $(tune-y) $(call cc-option,-mshort-load-bytes,$(call cc-option,-malignment-traps,)) -msoft-float -Uarm
 AFLAGS          +=$(CFLAGS_ABI) $(arch-y) $(tune-y) -msoft-float
 
 CHECKFLAGS      += -D__arm__
diff --git a/arch/arm/boot/compressed/Makefile b/arch/arm/boot/compressed/Makefile
index 6b8cbd69f249..5fde99f9d9f9 100644
--- a/arch/arm/boot/compressed/Makefile
+++ b/arch/arm/boot/compressed/Makefile
@@ -87,7 +87,7 @@ ifneq ($(PARAMS_PHYS),)
 LDFLAGS_vmlinux += --defsym params_phys=$(PARAMS_PHYS)
 endif
 LDFLAGS_vmlinux += -p --no-undefined -X \
-        $(shell $(CC) $(CFLAGS) --print-libgcc-file-name) -T
+        $(shell $(CC) $(KBUILD_CFLAGS) --print-libgcc-file-name) -T
 
 # Don't allow any static data in misc.o, which
 # would otherwise mess up our GOT table