um: clang: Strip out -mno-global-merge from USER_CFLAGS

The things built with USER_CFLAGS don't seem to recognise it as a
compiler option, and print a warning:
clang: warning: argument unused during compilation: '-mno-global-merge' [-Wunused-command-line-argument]

Fixes: 744814d2fa ("um: Allow builds with Clang")
Signed-off-by: David Gow <davidgow@google.com>
Reviewed-by: Nathan Chancellor <nathan@kernel.org>
Signed-off-by: Richard Weinberger <richard@nod.at>

diff --git a/arch/um/Makefile b/arch/um/Makefile
index f2fe63b..320b09c 100644 (file)
--- a/arch/um/Makefile
+++ b/arch/um/Makefile
@@ -75,6 +75,10 @@ USER_CFLAGS = $(patsubst $(KERNEL_DEFINES),,$(patsubst -I%,,$(KBUILD_CFLAGS))) \
                -D_FILE_OFFSET_BITS=64 -idirafter $(srctree)/include \
                -idirafter $(objtree)/include -D__KERNEL__ -D__UM_HOST__
 
+ifdef CONFIG_CC_IS_CLANG
+USER_CFLAGS := $(patsubst -mno-global-merge,,$(USER_CFLAGS))
+endif
+
 #This will adjust *FLAGS accordingly to the platform.
 include $(srctree)/$(ARCH_DIR)/Makefile-os-$(OS)