[XEN PATCH v7 48/51] build: Rework "headers*.chk" prerequisite in include/

[Anthony PERARD <anthony.perard@xxxxxxxxxx>]

Listing public headers when out-of-tree build are involved becomes
more annoying where every path to every headers needs to start with
"$(srctree)/$(src)", or $(wildcard ) will not work. This means more
repetition.

This patch attempt to reduce the amount of duplication and make better
use of make's meta programming capability. The filters are now listed
in a variable and don't have to repeat the path to the headers files
as this is added later as needed.

Signed-off-by: Anthony PERARD <anthony.perard@xxxxxxxxxx>
---
 xen/include/Makefile | 17 ++++++++++++++---
 1 file changed, 14 insertions(+), 3 deletions(-)

diff --git a/xen/include/Makefile b/xen/include/Makefile
index c3172f6636be..4e64a31ecab3 100644
--- a/xen/include/Makefile
+++ b/xen/include/Makefile
@@ -78,10 +78,21 @@ ifeq ($(XEN_TARGET_ARCH),$(XEN_COMPILE_ARCH))
 
 all: $(obj)/headers.chk $(obj)/headers99.chk $(obj)/headers++.chk
 
-PUBLIC_HEADERS := $(filter-out $(src)/public/arch-% $(src)/public/dom0_ops.h, 
$(wildcard $(src)/public/*.h $(src)/public/*/*.h))
+hdrs-path := $(srctree)/$(src)/public
 
-PUBLIC_C99_HEADERS := $(src)/public/io/9pfs.h $(src)/public/io/pvcalls.h
-PUBLIC_ANSI_HEADERS := $(filter-out $(src)/public/%ctl.h $(src)/public/xsm/% 
$(src)/public/%hvm/save.h $(PUBLIC_C99_HEADERS), $(PUBLIC_HEADERS))
+list-headers = $(wildcard $1/*.h $1/*/*.h)
+filter-headers = $(filter-out $(addprefix $(hdrs-path)/,$($1-filter)), $($1))
+
+c99-headers := io/9pfs.h io/pvcalls.h
+public-headers := $(call list-headers,$(hdrs-path))
+ansi-headers := $(public-headers)
+
+public-headers-filter := dom0_ops.h arch-%
+ansi-headers-filter := %ctl.h xsm/% %hvm/save.h $(public-headers-filter) 
$(c99-headers)
+
+PUBLIC_HEADERS := $(call filter-headers,public-headers)
+PUBLIC_ANSI_HEADERS := $(call filter-headers,ansi-headers)
+PUBLIC_C99_HEADERS := $(addprefix $(hdrs-path)/, $(c99-headers))
 
 $(src)/public/io/9pfs.h-prereq := string
 $(src)/public/io/pvcalls.h-prereq := string
-- 
Anthony PERARD