subdirmk/regen.mk.in: Trim `$(srcdir)/' prefix from output makefile names

[subdirmk.git] / subdirmk / regen.mk.in

diff --git a/subdirmk/regen.mk.in b/subdirmk/regen.mk.in
index e2944f08ffd3f8b8f7265639e38d0ba54c1ab399..948ef4e0791eccde5ab19c84215d20e5cc19a6a9 100644 (file)
--- a/subdirmk/regen.mk.in
+++ b/subdirmk/regen.mk.in
@@ -1,3 +1,7 @@
+# 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
@@ -12,18 +16,31 @@ $(top_srcdir)/$(CONFIGURE): $(addprefix $(top_srcdir)/,$(CONFIGURE_ACS))
 $(CONFIG_STATUS): $(top_srcdir)/$(CONFIGURE)
        ./$(CONFIG_STATUS) --recheck
 
-MAKEFILES += subdirmk/regen.mk
+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)                                \
-               $(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