kbuild: verify asm-generic header list

In order to integrate the system call header generation with generating
the asm-generic wrappers, restrict the generated headers to those that
actually exist in include/asm-generic/.

The path is already known, so add these as a dependency.

The asm-generic/bugs.h header was removed in commit 61235b24 ("init:
Remove check_bugs() leftovers"), which now causes a build failure, so
drop it from the list.
Signed-off-by: Arnd Bergmann <arnd@arndb.de>

include/asm-generic/Kbuild

@@ -9,7 +9,6 @@ mandatory-y += archrandom.h
 mandatory-y += barrier.h
 mandatory-y += bitops.h
 mandatory-y += bug.h
-mandatory-y += bugs.h
 mandatory-y += cacheflush.h
 mandatory-y += cfi.h
 mandatory-y += checksum.h

scripts/Makefile.asm-generic

@@ -46,7 +46,7 @@ all: $(generic-y)
 	$(if $(unwanted),$(call cmd,remove))
 	@:
 
-$(obj)/%.h:
+$(obj)/%.h: $(srctree)/$(generic)/%.h
 	$(call cmd,wrap)
 
 # Create output directory. Skip it if at least one old header exists