coccicheck: use --all-includes by default

Add a make variable, SPATCH_FLAGS, for specifying flags for spatch, and
set it to --all-includes by default.  This option lets it consider
header files which would otherwise be ignored.  That's important for
some rules that rely on type information.  It doubles the duration of
coccicheck, however.

Signed-off-by: Rene Scharfe <l.s.r@web.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

Makefile

@@ -467,6 +467,7 @@ SPATCH = spatch
 export TCL_PATH TCLTK_PATH
 
 SPARSE_FLAGS =
+SPATCH_FLAGS = --all-includes
 
 
 
@@ -2314,7 +2315,7 @@ C_SOURCES = $(patsubst %.o,%.c,$(C_OBJ))
 %.cocci.patch: %.cocci $(C_SOURCES)
 	@echo '    ' SPATCH $<; \
 	for f in $(C_SOURCES); do \
-		$(SPATCH) --sp-file $< $$f; \
+		$(SPATCH) --sp-file $< $$f $(SPATCH_FLAGS); \
 	done >$@ 2>$@.log; \
 	if test -s $@; \
 	then \