Vala: Add and test rebuild rules for generated header and vapi files.
valac will generate additional files when using, for example, -H in
VALAFLAGS. We need to recognize these options and add appropriate
rebuild rules to fix parallel build.
* automake.in (lang_vala_finish_target): Recognize -H, -h,
--header, --internal-header, --vapi, --internal-api, --gir flags
to valac and rebuild rules for generated headers; distribute
and maintainer-clean them.
* tests/vala2.test: Test rebuild rules.
Signed-off-by: Jürg Billeter <j@bitron.ch>
Signed-off-by: Ralf Wildenhues <Ralf.Wildenhues@gmx.de>