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/avr32/Makefile b/arch/avr32/Makefile
index dc6bc01f232c..9883c8b55e1b 100644
--- a/arch/avr32/Makefile
+++ b/arch/avr32/Makefile
@@ -11,14 +11,14 @@ all: uImage vmlinux.elf
 
 KBUILD_DEFCONFIG        := atstk1002_defconfig
 
-CFLAGS          += -pipe -fno-builtin -mno-pic
+KBUILD_CFLAGS   += -pipe -fno-builtin -mno-pic
 AFLAGS          += -mrelax -mno-pic
 CFLAGS_MODULE   += -mno-relax
 LDFLAGS_vmlinux += --relax
 
 cpuflags-$(CONFIG_CPU_AT32AP7000)       += -mcpu=ap7000
 
-CFLAGS          += $(cpuflags-y)
+KBUILD_CFLAGS   += $(cpuflags-y)
 AFLAGS          += $(cpuflags-y)
 
 CHECKFLAGS      += -D__avr32__ -D__BIG_ENDIAN