Merge "kbuild, x86: Track generated headers with generated-y"

		--- 7.1 header-y

		--- 7.2 genhdr-y

		--- 7.3 generic-y

		--- 7.4 generated-y

	=== 8 Kbuild Variables

	=== 9 Makefile language

		Example: termios.h

			#include <asm-generic/termios.h>

	--- 7.4 generated-y

	If an architecture generates other header files alongside generic-y

	wrappers, and not included in genhdr-y, then generated-y specifies

	them.

	This prevents them being treated as stale asm-generic wrappers and

	removed.

		Example:

			#arch/x86/include/asm/Kbuild

			generated-y += syscalls_32.h

=== 8 Kbuild Variables

The top Makefile exports the following variables:

generated-y += syscalls_32.h

generated-y += syscalls_64.h

generated-y += unistd_32_ia32.h

generated-y += unistd_64_x32.h

generated-y += xen-hypercalls.h

genhdr-y += unistd_32.h

genhdr-y += unistd_64.h

genhdr-y += unistd_x32.h

# Create output directory if not already present

_dummy := $(shell [ -d $(obj) ] || mkdir -p $(obj))

# Stale wrappers when the corresponding files are removed from generic-y

# need removing.

generated-y   := $(generic-y) $(genhdr-y) $(generated-y)

all-files     := $(patsubst %, $(obj)/%, $(generated-y))

old-headers   := $(wildcard $(obj)/*.h)

unwanted      := $(filter-out $(all-files),$(old-headers))

quiet_cmd_wrap = WRAP    $@

cmd_wrap = echo "\#include <asm-generic/$*.h>" >$@

all: $(patsubst %, $(obj)/%, $(generic-y))

quiet_cmd_remove = REMOVE  $(unwanted)

cmd_remove = rm -f $(unwanted)

all: $(patsubst %, $(obj)/%, $(generic-y)) FORCE

	$(if $(unwanted),$(call cmd,remove),)

	@:

$(obj)/%.h:

	$(call cmd,wrap)

PHONY += FORCE

.PHONY: $(PHONY)

FORCE: ;