build: add convenience target 'build-sources'

This target allows to trigger a build of $(BUILT_SOURCES) manually. This
is handy if you tend to use 'make systemd-foobar' to directly build a
single binary. Those do not pull in $(BUILT_SOURCES), unfortunately. See
automake docs for that.

diff --git a/Makefile.am b/Makefile.am
index c038fed36b21d3dfc03482348c6e566629522522..3c0ce32692bf2d6ff73acb15cf71b9dcad889807 100644 (file)
--- a/Makefile.am
+++ b/Makefile.am
@@ -6139,6 +6139,9 @@ hwdb-update:
                http://standards.ieee.org/develop/regauth/iab/iab.txt && \
        ./ids-update.pl )
 
+.PHONY: built-sources
+built-sources: $(BUILT_SOURCES)
+
 .PHONY: git-tag
 git-tag:
        git tag -s "v$(VERSION)" -m "systemd $(VERSION)"