Hi Daniel,

    Attached you'll find a patch for this bug, including some improvements to
    Vala support.

Thanks again for this patch and the copyright assignment.

Unfortunately, after locally applying the patch, several of
your new tests fail with make (dist)check, as well as some of the
existing vala tests.
    FAIL: t/vala-headers.sh
    FAIL: t/vala-libs-distcheck.sh
    FAIL: t/vala-non-recursive-setup.sh
    FAIL: t/vala-parallel.sh
    FAIL: t/vala-recursive-setup.sh
    FAIL: t/vala-vpath.sh

Looking at the logs, for instance for vala-vpath.sh, the
  test -f ../foo_vala.stamp
from the build/ subdir does not find the file, since the stamp files are
also in the build/ subdir. Which seems correct, but I am not sure what's
intentional and what's erroneous.

Any chance you can look into this? I will attach the patch as I have it
locally now. (This is the output from git diff --staged; if it's easier
for you work with format-patch output, just let me know.)

There were a couple other vala-related changes made between now and when
you submitted the patch, but I don't think they affect your work. Here
are their ChangeLog entries:

2020-06-06  Karl Berry  <karl@freefriends.org>

	This change fixes https://bugs.gnu.org/41726.
	* t/vala-mix2.sh: extern in .h, initialization in .c.
	GCC 10 defaults to -fno-common.

2020-04-05  Colomban Wendling  <lists.ban@herbesfolles.org>

	This change fixes https://bugs.gnu.org/18734.
	* bin/automake.in (lang_vala_finish_target): anchor option regexp
	so that, e.g., an argument "vapi" does not match the option --vapi.