X-Git-Url: https://www.chiark.greenend.org.uk/ucgi/~ian/git?a=blobdiff_plain;f=subdirmk%2Fregen.mk.in;h=a6d9ad2544837b83b5d2ee2386b1328fe69cb430;hb=b48380652d2974f9d615a5c942a82f3dfb002ca3;hp=e2944f08ffd3f8b8f7265639e38d0ba54c1ab399;hpb=4800c931218887da8996d827a9351335e1e7e5f1;p=subdirmk.git

diff --git a/subdirmk/regen.mk.in b/subdirmk/regen.mk.in
index e2944f0..a6d9ad2 100644
--- a/subdirmk/regen.mk.in
+++ b/subdirmk/regen.mk.in
@@ -1,10 +1,14 @@
+# subdirmk - rules for regenerating makefiles etc.
+#  Copyright 2019 Mark Wooding
+#  Copyright 2019 Ian Jackson
+# SPDX-License-Identifier: LGPL-2.0-or-later
 
 CONFIGURE	?= configure
-CONFIGURE_AC 	?= $(CONFIGURE).ac
-CONFIG_STATUS 	?= config.status
+CONFIGURE_AC	?= $(CONFIGURE).ac
+CONFIG_STATUS	?= config.status
 
-CONFIGURE_ACS 	+= $(CONFIGURE_AC)
-CONFIGURE_ACS 	+= subdirmk/subdirmk.ac
+CONFIGURE_ACS	+= $(CONFIGURE_AC)
+CONFIGURE_ACS	+= subdirmk/subdirmk.ac
 
 $(top_srcdir)/$(CONFIGURE): $(addprefix $(top_srcdir)/,$(CONFIGURE_ACS))
 	cd $(top_srcdir) && autoconf
@@ -12,23 +16,36 @@ $(top_srcdir)/$(CONFIGURE): $(addprefix $(top_srcdir)/,$(CONFIGURE_ACS))
 $(CONFIG_STATUS): $(top_srcdir)/$(CONFIGURE)
 	./$(CONFIG_STATUS) --recheck
 
-MAKEFILES += subdirmk/regen.mk
+# Normally, generate will add all the inputs to MAKEFILE_TEMPLATES.
+MAKEFILE_TEMPLATES += $(addprefix $(top_srcdir)/, $(addsuffix .in, \
+	@_SUBDIRMK_MAKEFILES@ \
+	))
 
 main.mk $(MAKEFILES): .makefiles.stamp ;
-.makefiles.stamp: 						\
+.makefiles.stamp:						\
 		$(top_srcdir)/subdirmk/generate			\
 		$(CONFIG_STATUS)				\
-		$(top_srcdir)/Perdir.mk.in			\
-		$(foreach m,$(MAKEFILES),$(top_srcdir)/$(m).in)
-	: $? X $(filter-out Subdir.mk.in regen.mk.in, $(notdir $?))
+		$(MAKEFILE_TEMPLATES)
+# This filtering arranges that we can often run config.status to
+# generate only particular output files.  We look for *inputs* that
+# have changed.  If the only inputs that have changed are ones that we
+# know affect only one output (Subdir.mk.in and regen.mk.in), we pass
+# config.status the corresponding output file names.  Otherwise we
+# pass nothing and config.status does them all.  We need to mention
+# regen.mk.in twice because if $(top_srcdir) is `.', make elides the
+# directory part from $?.
 	./$(CONFIG_STATUS) $(if					\
-		$(filter-out Subdir.mk.in regen.mk.in, $(notdir $?)),,	\
-		$(patsubst %.mk.in,%.mk,$(filter %.mk.in,$?)))
+		$(filter-out Subdir.sd.mk %/Subdir.sd.mk	\
+			     %.mk.in				\
+			, $?),,					\
+		$(patsubst $(top_srcdir)/%,%, $(sort		\
+			$(patsubst %.sd.mk,%.mk,$(filter %.sd.mk,$?)) \
+			$(patsubst %.mk.in,%.mk,$(filter %.mk.in,$?)))))
 	touch $@
 
 realclean:: clean
 	$(RM) config.status config.log
-	$(RM) main.mk subdirmk/regen.mk $(MAKEFILES)
+	$(RM) main.mk $(MAKEFILES) @_SUBDIRMK_MAKEFILES@
 	$(RM) $(addsuffix Makefile,$(dir $(MAKEFILES)))
 
 -include $(ALL_DEPFILES)