systemd's meson.build looks up various systems utilties at build-time.
This wasn't a problem before, but as our buildroots are now usr-merged
we can no longer expect that meson's $PATH traversal results in a path
to a binary on non-usr-merge system. We need to state our expectations
explictly now.
This also removes some unneeded options. meson's get_option returns on
booleans without any default `true`.
Part-of: https://gitlab.postmarketos.org/postmarketOS/pmaports/-/merge_requests/6884
[ci:skip-build]: already built successfully in CI
Jane Rachinger
2edc560b12