kbuild: Allow arch Makefiles to override {cpp,ld,c}flags
Since commit a1c48bb1 (Makefile: Fix unrecognized cross-compiler command
line options), the arch Makefile is included earlier by the main
Makefile, preventing the arc architecture to set its -O3 compiler
option. Since there might be more use cases for an arch Makefile to
fine-tune the options, add support for ARCH_CPPFLAGS, ARCH_AFLAGS and
ARCH_CFLAGS variables that are appended to the respective kbuild
variables. The user still has the final say via the KCPPFLAGS, KAFLAGS
and KCFLAGS variables.
Reported-by: Vineet Gupta <Vineet.Gupta1@synopsys.com>
Cc: stable@vger.kernel.org # 3.16+
Signed-off-by: Michal Marek <mmarek@suse.com>
diff --git a/Makefile b/Makefile
index 13270c0..8c31fbc 100644
--- a/Makefile
+++ b/Makefile
@@ -780,10 +780,11 @@
include scripts/Makefile.kasan
include scripts/Makefile.extrawarn
-# Add user supplied CPPFLAGS, AFLAGS and CFLAGS as the last assignments
-KBUILD_CPPFLAGS += $(KCPPFLAGS)
-KBUILD_AFLAGS += $(KAFLAGS)
-KBUILD_CFLAGS += $(KCFLAGS)
+# Add any arch overrides and user supplied CPPFLAGS, AFLAGS and CFLAGS as the
+# last assignments
+KBUILD_CPPFLAGS += $(ARCH_CPPFLAGS) $(KCPPFLAGS)
+KBUILD_AFLAGS += $(ARCH_AFLAGS) $(KAFLAGS)
+KBUILD_CFLAGS += $(ARCH_CFLAGS) $(KCFLAGS)
# Use --build-id when available.
LDFLAGS_BUILD_ID = $(patsubst -Wl$(comma)%,%,\