[PATCH] kbuild: fix compile time regression

[Arnd Bergmann]

I noticed that a patch I did causes the time for a clean rebuild to
go up significantly, from 13 to 18 seconds on ARM defconfig, and
in the worst case forcing a rebuild of every file each time.

The fix is very simple, using a ':=' assignment instead of '='
to force the cc-disable-warning call to only be evaluated once
instead of every time.

Signed-off-by: Arnd Bergmann <arnd@xxxxxxxx>
---
 Makefile | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/Makefile b/Makefile
index 3a964fa3a787..e7d4d20deb4e 100644
--- a/Makefile
+++ b/Makefile
@@ -381,7 +381,7 @@ LDFLAGS_MODULE  =
 CFLAGS_KERNEL	=
 AFLAGS_KERNEL	=
 LDFLAGS_vmlinux =
-CFLAGS_GCOV	= -fprofile-arcs -ftest-coverage -fno-tree-loop-im $(call cc-disable-warning,maybe-uninitialized,)
+CFLAGS_GCOV	:= -fprofile-arcs -ftest-coverage -fno-tree-loop-im $(call cc-disable-warning,maybe-uninitialized,)
 CFLAGS_KCOV	:= $(call cc-option,-fsanitize-coverage=trace-pc,)
 
 ifeq ($(COMPILER),clang)
-- 
2.9.0