mesonlib: allow check_dirent_issues to take an iterable
mesonlib: allow check_dirent_issues to take an iterable

There's no reason it needs a concrete list, any iterable is fine. This
does mean that we need to explicitly check for `str | bytes` in the
listify pass, as `str` and `bytes` are both iterable.

mesonbuild/meson,pexip/meson,pexip/meson,mesonbuild/meson,pexip/meson,pexip/meson,mesonbuild/meson,pexip/meson,pexip/meson,mesonbuild/meson,mesonbuild/meson,pexip/meson,mesonbuild/meson,mesonbuild/meson,mesonbuild/meson,pexip/meson,pexip/meson,pexip/meson,mesonbuild/meson,mesonbuild/meson