diff --git a/[refs] b/[refs]
index f6d7e8151e9d..b7b60b5a720f 100644
--- a/[refs]
+++ b/[refs]
@@ -1,2 +1,2 @@
 ---
-refs/heads/master: 4f40c05528f9d612057a3dd382008a54179f8919
+refs/heads/master: f15cf5151c3ecfe4073fb4478f686cb396bc2b17
diff --git a/trunk/arch/um/Makefile b/trunk/arch/um/Makefile
index 82c2ac48040d..768a5d14b755 100644
--- a/trunk/arch/um/Makefile
+++ b/trunk/arch/um/Makefile
@@ -70,9 +70,12 @@ include $(srctree)/$(ARCH_DIR)/Makefile-os-$(OS)
 # in KBUILD_CFLAGS.  Otherwise, it would cause ld to complain about the two different
 # errnos.
 # These apply to kernelspace only.
+#
+# strip leading and trailing whitespace to make the USER_CFLAGS removal of these
+# defines more robust
 
-KERNEL_DEFINES = -Derrno=kernel_errno -Dsigprocmask=kernel_sigprocmask \
-	-Dmktime=kernel_mktime $(ARCH_KERNEL_DEFINES)
+KERNEL_DEFINES = $(strip -Derrno=kernel_errno -Dsigprocmask=kernel_sigprocmask \
+			 -Dmktime=kernel_mktime $(ARCH_KERNEL_DEFINES))
 KBUILD_CFLAGS += $(KERNEL_DEFINES)
 KBUILD_CFLAGS += $(call cc-option,-fno-unit-at-a-time,)