This is required since Meson 0.61.0, and causes a warning to be
emitted otherwise:
2c079d855e
https://github.com/mesonbuild/meson/issues/9300
This exposed a bunch of places where we had broken run_command()
calls, unnecessary run_command() calls, and places where check: true
should be used.
Part-of: <https://gitlab.freedesktop.org/gstreamer/gstreamer/-/merge_requests/1507>