X-Git-Url: http://www.chiark.greenend.org.uk/ucgi/~ianmdlvl/git?a=blobdiff_plain;f=subdirmk%2Fregen.mk.in;h=5f24b08fd4e504cc50019a276df7850abb9b9dbf;hb=24eb6b672f1095d5b362b6615f22c17f1136274a;hp=0e8bb6a3245ddc82e8508a7119848c813da4e6da;hpb=8d746a1d7b875ae2118247d08e944f2fd7700e8a;p=secnet.git

diff --git a/subdirmk/regen.mk.in b/subdirmk/regen.mk.in
index 0e8bb6a..5f24b08 100644
--- a/subdirmk/regen.mk.in
+++ b/subdirmk/regen.mk.in
@@ -1,17 +1,66 @@
+# subdirmk - rules for regenerating makefiles etc.
+#  Copyright 2019 Mark Wooding
+#  Copyright 2019 Ian Jackson
+# SPDX-License-Identifier: LGPL-2.0-or-later
+
+# Usage:
+#   include subdirmk/regen.mk
+# (probably in toplevel Subdir.sd.mk)
+#
+# Arranges that config.status is automatically rerun to update
+# makefiles from templates, whenever a template *.sd.mk or *.mk.in is
+# edited; and that autoconf is rerun if configure's inputs are edited.
+#
+# If you add includes to configure.ac, add them to CONFIGURE_ACS.
+#
+# Also provides a `realclean::' target at the toplevel which deletes
+# the autoconf output.  This may be made into a recursive target
+# by mentioning &TARGETS_realclean in appropriate .sd.mk.
 
 CONFIGURE	?= configure
-CONFIGURE_AC 	?= $(CONFIGURE).ac
-CONFIG_STATUS 	?= config.status
-SUBDIRMK	?= subdirmk
+CONFIGURE_AC	?= $(CONFIGURE).ac
+CONFIG_STATUS	?= config.status
+
+CONFIGURE_ACS	+= $(CONFIGURE_AC)
+CONFIGURE_ACS	+= subdirmk/subdirmk.ac
 
-&^/$(CONFIGURE): &^/$(CONFIGURE_AC)
-	cd &^ && autoconf
+$(top_srcdir)/$(CONFIGURE): $(addprefix $(top_srcdir)/,$(CONFIGURE_ACS))
+	cd $(top_srcdir) && autoconf
 
-$(CONFIG_STATUS): &^/$(CONFIGURE)
+$(CONFIG_STATUS): $(top_srcdir)/$(CONFIGURE)
 	./$(CONFIG_STATUS) --recheck
 
-all-subdirs.mk $(MAKFILES): makefiles.phantom
-.INTERMEDIATE: makefiles.phantom
-makefiles.phantom: $(addprefix &^/,$(addsuffix .in,$(MAKEFILES)))	\
-		$(CONFIG_STATUS) &^/$(SUBDIRMK)/generate
-	./$(CONFIG_STATUS)
+# Normally, generate will add all the inputs to MAKEFILE_TEMPLATES.
+MAKEFILE_TEMPLATES += $(addprefix $(top_srcdir)/, $(addsuffix .in, \
+	@_SUBDIRMK_MAKEFILES@ \
+	))
+
+main.mk $(SUBDIRMK_MAKEFILES) $(CONFIG_STATUS_OUTPUTS): .makefiles.stamp
+		@:
+.makefiles.stamp:						\
+		$(top_srcdir)/subdirmk/generate			\
+		$(CONFIG_STATUS)				\
+		$(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.sd.mk and *.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
+# Subdir.sd.mk twice because if $(top_srcdir) is `.', make elides the
+# directory part from $?.
+	./$(CONFIG_STATUS) $(if					\
+		$(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_MAKEFILES) @_SUBDIRMK_MAKEFILES@
+	$(RM) $(addsuffix Makefile,$(dir $(SUBDIRMK_MAKEFILES)))
+
+-include $(ALL_DEPFILES)