The meson-build procedure is integrated into CI to catch and
prevent bitrotting.
* ps/ci-meson:
ci: wire up Meson builds
t: introduce compatibility options to clar-based tests
t: fix out-of-tree tests for some git-p4 tests
Makefile: detect missing Meson tests
meson: detect missing tests at configure time
t/unit-tests: rename clar-based unit tests to have a common prefix
Makefile: drop -DSUPPRESS_ANNOTATED_LEAKS
ci/lib: support custom output directories when creating test artifacts