[libglnx] (4 commits) Non-fast-forward update to branch wip/smcv/subproject

[Simon McVittie <smcv src gnome org>]

The branch 'wip/smcv/subproject' was changed in a way that was not a fast-forward update.
NOTE: This may cause problems for people pulling from the branch. For more information,
please see:

 https://wiki.gnome.org/Git/Help/NonFastForward

Commits removed from the branch:

  670a4be... tests: Build libglnx-testlib as a separate static library
  2adc8c5... tests: Optionally skip building and running the actual test
  5e226d3... tests: Verify libglnx can work as a subproject
  f9012dd... meson: Always build with hidden symbol visibility

Commits added to the branch:

  2c20127... tests: Build libglnx-testlib as a separate static library
  129ecb2... tests: Optionally skip building and running the actual test
  bdfef34... tests: Verify libglnx can work as a subproject
  3d53b81... meson: Always build with hidden symbol visibility