kbuild: generate include/generated/compile.h in top Makefile

Now that UTS_VERSION was separated out, this header can be generated
much earlier, and probably the top Makefile is a better place to do it
than init/Makefile.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>

Makefile

@@ -1194,7 +1194,7 @@ PHONY += prepare archprepare
 
 archprepare: outputmakefile archheaders archscripts scripts include/config/kernel.release \
 	asm-generic $(version_h) $(autoksyms_h) include/generated/utsrelease.h \
-	include/generated/autoconf.h remove-stale-files
+	include/generated/compile.h include/generated/autoconf.h remove-stale-files
 
 prepare0: archprepare
 	$(Q)$(MAKE) $(build)=scripts/mod
@@ -1256,6 +1256,12 @@ $(version_h): FORCE
 include/generated/utsrelease.h: include/config/kernel.release FORCE
 	$(call filechk,utsrelease.h)
 
+filechk_compile.h = $(srctree)/scripts/mkcompile_h \
+	"$(UTS_MACHINE)" "$(CONFIG_CC_VERSION_TEXT)" "$(LD)"
+
+include/generated/compile.h: FORCE
+	$(call filechk,compile.h)
+
 PHONY += headerdep
 headerdep:
 	$(Q)find $(srctree)/include/ -name '*.h' | xargs --max-args 1 \

init/Makefile

@@ -45,15 +45,9 @@ $(obj)/utsversion-tmp.h: FORCE
 
 clean-files += utsversion-tmp.h
 
-$(obj)/version.o: include/generated/compile.h $(obj)/utsversion-tmp.h
+$(obj)/version.o: $(obj)/utsversion-tmp.h
 CFLAGS_version.o := -include $(obj)/utsversion-tmp.h
 
-filechk_compile.h = $(srctree)/scripts/mkcompile_h \
-	"$(UTS_MACHINE)" "$(CONFIG_CC_VERSION_TEXT)" "$(LD)"
-
-include/generated/compile.h: FORCE
-	$(call filechk,compile.h)
-
 #
 # Build version-timestamp.c with final UTS_VERSION
 #