CONFIGURE ?= configure
CONFIGURE_AC ?= $(CONFIGURE).ac
CONFIG_STATUS ?= config.status
-SUBDIRMK ?= subdirmk
-&^/$(CONFIGURE): &^/$(CONFIGURE_AC)
- cd &^ && autoconf
+CONFIGURE_ACS += $(CONFIGURE_AC)
+CONFIGURE_ACS += subdirmk/subdirmk.ac
-$(CONFIG_STATUS): &^/$(CONFIGURE)
+$(top_srcdir)/$(CONFIGURE): $(addprefix $(top_srcdir)/,$(CONFIGURE_ACS))
+ cd $(top_srcdir) && autoconf
+
+$(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)
+MAKEFILE_TEMPLATES += $(top_srcdir)/Perdir.sd.mk
+MAKEFILE_TEMPLATES += $(addprefix $(top_srcdir)/, $(addsuffix .in, \
+ @_SUBDIRMK_MAKEFILES@ \
+ ))
+
+main.mk $(MAKEFILES): .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.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.sd.mk %/Subdir.sd.mk \
+ %.mk.in \
+ , $?),, \
+ $(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) $(addsuffix Makefile,$(dir $(MAKEFILES)))
+
+-include $(ALL_DEPFILES)