1 files changed, 6 insertions, 1 deletions

diff --git a/Makefile b/Makefile
index 9193f94ddf83..7d4e9c8da729 100644
--- a/Makefile
+++ b/Makefile
@@ -102,6 +102,10 @@ ifeq ("$(origin O)", "command line")
   KBUILD_OUTPUT := $(O)
 endif
 
+ifeq ("$(origin W)", "command line")
+  export KBUILD_ENABLE_EXTRA_GCC_CHECKS := 1
+endif
+
 # That's our default target when none is given on the command line
 PHONY := _all
 _all:
@@ -1018,7 +1022,7 @@ hdr-dst = $(if $(KBUILD_HEADERS), dst=include/asm-$(hdr-arch), dst=include/asm)
 
 PHONY += __headers
 __headers: include/linux/version.h scripts_basic FORCE
-        $(Q)$(MAKE) $(build)=scripts scripts/unifdef
+        $(Q)$(MAKE) $(build)=scripts build_unifdef
 
 PHONY += headers_install_all
 headers_install_all:
@@ -1263,6 +1267,7 @@ help:
         @echo  '  make O=dir [targets] Locate all output files in "dir", including .config'
         @echo  '  make C=1   [targets] Check all c source with $$CHECK (sparse by default)'
         @echo  '  make C=2   [targets] Force check of all c source with $$CHECK'
+        @echo  '  make W=1   [targets] Enable extra gcc checks'
         @echo  ''
         @echo  'Execute "make" or "make all" to build all targets marked with [*] '
         @echo  'For further info see the ./README file'