Merge branch 'meson' of https://github.com/t-8ch/util-linux

* 'meson' of https://github.com/t-8ch/util-linux:
  meson: only install pkgconfig if library is built
  meson: install manpages and bash completions
  meson: install examples to correct directory
  meson: headers: Install headers
  meson: headers: use util-linux version of version defines