I have not found any documentation about hooking recipes with custom (non-depcomp) tools into Automake's automatic dependency tracking, so this describes what I have done to achieve that along with a few questions.
If you want the complete code example, see the git branch at https://github.com/ndim/xnec2c/tree/buildsystem-cleanups which is part of the Pull Request https://github.com/KJ7LNW/xnec2c/pull/17. The following text describes a simplified version of the xnec2c case. The glib-compile-resources tool generates a *.c file from an *.xml file and possibly some files included from that *.xml file. Fortunately, the glib-compile-resources tool can also create a dependency file for inclusion into Makefile as a side-effect of compilation, but obviously Automake/depcomp do not know about glib-compile-resources and therefore I need to hook that into Makefile.am myself. Automake does automatic dependency tracking via one ./$(DEPDIR)/*.Po file listed in the am__depfiles_remade make var per *.c source file, and then one include line per *.Po file and a recipe with $(am__depfiles_remade) target and no dependencies which creates a dummy no-op *.Po file to be used before the first actual compilation. (The first compilation will later create the *.Po file containing actual file dependencies.) include ./$(DEPDIR)/bar.Po # am--include-marker include ./$(DEPDIR)/main.Po # am--include-marker $(am__depfiles_remade): @$(MKDIR_P) $(@D) @echo '# dummy' >$@-t && $(am__mv) $@-t $@ Mimicking what the depcomp-based automatic dependency tracking does without relying on its internals, I "include" my own dependency file and provide an explicit recipe to create a dummy dep file to use before the first compilation happens, and also make sure that it is removed at "make distclean" like the *.Po files are: DISTCLEANFILES += ./$(DEPDIR)/foo-resources.cdep include ./$(DEPDIR)/foo-resources.cdep ./$(DEPDIR)/foo-resources.cdep: @$(MKDIR_P) $(@D) @echo '# dummy' >$@-t && $(am__mv) $@-t $@ Luckily, the "include" line is copied verbatim from Makefile.am to Makefile.in and Makefile and not evaluated by Automake, so this works. Then I must write the recipe which does the actual compilation with the side effect of generating the dependency file: foo_SOURCES += foo-resources.c CLEANFILES += foo-resources.c foo-resources.c: $(srcdir)/foo.gresource.xml $(GLIB_COMPILE_RESOURCES) \ --sourcedir=$(srcdir) \ --dependency-file=./$(DEPDIR)/foo-resources.cdep \ --target=foo-resources.c \ --generate-source \ $(srcdir)/foo.gresource.xml As foo-resources.c is listed in foo_SOURCES, I do not need to list it in BUILT_SOURCES. Also, the generated file should be cleaned. Then the recipe both creates the *.c file from *.xml (and whatever that *.xml includes internally), and creates the dependency file from the internal includes. Question: Is it OK for me to hook into ./$(DEPDIR)/ at all? I could use just some file in $(builddir), after all. Question: Is *.cdep a good name? I want to avoid name collisions. Question: Is it ok for me to use $(am__mv)? Documentation used: 2.2.12 Automatic Dependency Tracking https://www.gnu.org/software/automake/manual/automake.html#Dependency-Tracking 8.19 Automatic dependency tracking https://www.gnu.org/software/automake/manual/automake.html#Dependencies
