diff --git a/Makefile b/Makefile
index 5aba1ac89375..a4ac0133f7cd 100644
--- a/Makefile
+++ b/Makefile
@@ -1041,8 +1041,10 @@ ifdef CONFIG_CC_IS_GCC
 KBUILD_CFLAGS   += -fconserve-stack
 endif
 
-# change __FILE__ to the relative path from the srctree
-KBUILD_CPPFLAGS += $(call cc-option,-fmacro-prefix-map=$(srctree)/=)
+# change __FILE__ to the relative path to the source directory
+ifdef building_out_of_srctree
+KBUILD_CPPFLAGS += $(call cc-option,-fmacro-prefix-map=$(srcroot)/=)
+endif
 
 # include additional Makefiles when needed
 include-y			:= scripts/Makefile.extrawarn