diff --git a/Makefile b/Makefile
index b38ea3ed8b..334d62a0a7 100644
--- a/Makefile
+++ b/Makefile
@@ -583,18 +583,23 @@ endif
 # and from include/config/auto.conf.cmd to detect the compiler upgrade.
 CC_VERSION_TEXT = $(subst $(pound),,$(shell $(CC) --version 2>/dev/null | head -n 1))
 
-ifneq ($(findstring clang,$(CC_VERSION_TEXT)),)
+TENTATIVE_CLANG_FLAGS := -Werror=unknown-warning-option
+
 ifneq ($(CROSS_COMPILE),)
-CLANG_FLAGS	+= --target=$(notdir $(CROSS_COMPILE:%-=%))
+TENTATIVE_CLANG_FLAGS	+= --target=$(notdir $(CROSS_COMPILE:%-=%))
 endif
 ifeq ($(LLVM_IAS),1)
-CLANG_FLAGS	+= -integrated-as
+TENTATIVE_CLANG_FLAGS	+= -integrated-as
 else
-CLANG_FLAGS	+= -no-integrated-as
+TENTATIVE_CLANG_FLAGS	+= -no-integrated-as
 GCC_TOOLCHAIN_DIR := $(dir $(shell which $(CROSS_COMPILE)elfedit))
-CLANG_FLAGS	+= --prefix=$(GCC_TOOLCHAIN_DIR)$(notdir $(CROSS_COMPILE))
+TENTATIVE_CLANG_FLAGS	+= --prefix=$(GCC_TOOLCHAIN_DIR)$(notdir $(CROSS_COMPILE))
 endif
-CLANG_FLAGS	+= -Werror=unknown-warning-option
+
+export TENTATIVE_CLANG_FLAGS
+
+ifneq ($(findstring clang,$(CC_VERSION_TEXT)),)
+CLANG_FLAGS	+= $(TENTATIVE_CLANG_FLAGS)
 KBUILD_CFLAGS	+= $(CLANG_FLAGS)
 KBUILD_AFLAGS	+= $(CLANG_FLAGS)
 export CLANG_FLAGS