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, 5 insertions, 5 deletions

diff --git a/arch/i386/Makefile b/arch/i386/Makefile
index 5e50dbf00f3e..fc3c8e88b744 100644
--- a/arch/i386/Makefile
+++ b/arch/i386/Makefile
@@ -34,10 +34,10 @@ LDFLAGS_vmlinux := --emit-relocs
 endif
 CHECKFLAGS      += -D__i386__
 
-CFLAGS += -pipe -msoft-float -mregparm=3 -freg-struct-return
+KBUILD_CFLAGS += -pipe -msoft-float -mregparm=3 -freg-struct-return
 
 # prevent gcc from keeping the stack 16 byte aligned
-CFLAGS += $(call cc-option,-mpreferred-stack-boundary=2)
+KBUILD_CFLAGS += $(call cc-option,-mpreferred-stack-boundary=2)
 
 # CPU-specific tuning. Anything which can be shared with UML should go here.
 include $(srctree)/arch/i386/Makefile.cpu
@@ -51,7 +51,7 @@ cflags-y += -maccumulate-outgoing-args
 
 # Disable unit-at-a-time mode on pre-gcc-4.0 compilers, it makes gcc use
 # a lot more stack due to the lack of sharing of stacklots:
-CFLAGS                          += $(shell if [ $(call cc-version) -lt 0400 ] ; then echo $(call cc-option,-fno-unit-at-a-time); fi ;)
+KBUILD_CFLAGS += $(shell if [ $(call cc-version) -lt 0400 ] ; then echo $(call cc-option,-fno-unit-at-a-time); fi ;)
 
 # do binutils support CFI?
 cflags-y += $(call as-instr,.cfi_startproc\n.cfi_rel_offset esp${comma}0\n.cfi_endproc,-DCONFIG_AS_CFI=1,)
@@ -61,7 +61,7 @@ AFLAGS += $(call as-instr,.cfi_startproc\n.cfi_rel_offset esp${comma}0\n.cfi_end
 cflags-y += $(call as-instr,.cfi_startproc\n.cfi_signal_frame\n.cfi_endproc,-DCONFIG_AS_CFI_SIGNAL_FRAME=1,)
 AFLAGS += $(call as-instr,.cfi_startproc\n.cfi_signal_frame\n.cfi_endproc,-DCONFIG_AS_CFI_SIGNAL_FRAME=1,)
 
-CFLAGS += $(cflags-y)
+KBUILD_CFLAGS += $(cflags-y)
 
 # Default subarch .c files
 mcore-y  := arch/x86/mach-default
@@ -116,7 +116,7 @@ drivers-$(CONFIG_OPROFILE)		+= arch/x86/oprofile/
 drivers-$(CONFIG_PM)                    += arch/x86/power/
 drivers-$(CONFIG_FB)                    += arch/x86/video/
 
-CFLAGS += $(mflags-y)
+KBUILD_CFLAGS += $(mflags-y)
 AFLAGS += $(mflags-y)
 
 boot := arch/x86/boot