[XEN PATCH for-4.17 v5 13/17] libs/light: Rework generation of include/_libxl_*.h

[Anthony PERARD <anthony.perard@xxxxxxxxxx>]

Instead of moving the public "_libxl_*.h" headers, we make a copy to
the destination so that make doesn't try to remake the targets
"_libxl_*.h" in libs/light/ again.

A new .PRECIOUS target is added to tell make to not deletes the
intermediate targets generated by "gentypes.py".

Signed-off-by: Anthony PERARD <anthony.perard@xxxxxxxxxx>
---

Notes:
    v4:
    - new patch

 tools/libs/light/Makefile | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/tools/libs/light/Makefile b/tools/libs/light/Makefile
index 4a8b0f7bcf..9329055c98 100644
--- a/tools/libs/light/Makefile
+++ b/tools/libs/light/Makefile
@@ -215,6 +215,8 @@ libxl_internal_json.h: _libxl_types_internal_json.h
 $(OBJS-y) $(PIC_OBJS) $(LIBXL_TEST_OBJS) $(TEST_PROG_OBJS) 
$(SAVE_HELPER_OBJS): $(XEN_INCLUDE)/libxl.h
 $(OBJS-y) $(PIC_OBJS) $(LIBXL_TEST_OBJS): libxl_internal.h
 
+# This exploits the 'multi-target pattern rule' trick.
+# gentypes.py should be executed only once to make all the targets.
 _libxl_type%.h _libxl_type%_json.h _libxl_type%_private.h _libxl_type%.c: 
libxl_type%.idl gentypes.py idl.py
        $(eval stem = $(notdir $*))
        $(PYTHON) gentypes.py libxl_type$(stem).idl __libxl_type$(stem).h 
__libxl_type$(stem)_private.h \
@@ -224,8 +226,10 @@ _libxl_type%.h _libxl_type%_json.h _libxl_type%_private.h 
_libxl_type%.c: libxl_
        $(call 
move-if-changed,__libxl_type$(stem)_json.h,_libxl_type$(stem)_json.h)
        $(call move-if-changed,__libxl_type$(stem).c,_libxl_type$(stem).c)
 
-$(XEN_INCLUDE)/_%.h: _%.h
-       $(call move-if-changed,_$*.h,$(XEN_INCLUDE)/_$*.h)
+.PRECIOUS: _libxl_type%.h _libxl_type%.c
+
+$(XEN_INCLUDE)/_libxl_%.h: _libxl_%.h
+       cp -f $< $@
 
 .PHONY: acpi
 acpi:
-- 
Anthony PERARD