That dependency was causing a failure when building from a fresh
checkout since commit d60225d5ca because
'guix-manual.pot' was no longer around and there's no rule to make it.
This commit replaces the 'guix-manual.%.po' target by a phony target,
'doc-po-update-%', without any dependency.
* po/doc/local.mk ($(srcdir)/po/doc/guix-manual.%.po): Rename to...
(doc-po-update-%): ... this. Remove dependencies.
Change how 'lang' is computed; compute $output and $input, and replace
occurrences of $@ and $< with those.
(doc-po-update): Adjust accordingly.
* po/doc/contributing.pot: New file.
* po/doc/guix.pot: New file.
* po/doc/local.mk: New file.
* Makefile.am: Include it. Add gettext command. Add silent rules for po4a.
* configure.ac: Look for po4a-translate and po4a-updatepo.
* doc/local.mk: Add rules to generate translated texi files.
(TRANSLATED_INFO): New variable.
(BUILT_SOURCES, EXTRA_DIST, MAINTAINERCLEANFILES): Add it.
* .gitignore: Add generated files.
Ludovic Courtès