[gtk+] (5 commits) Non-fast-forward update to branch wip/ebassi/legacy-gl

[Emmanuele Bassi <ebassi src gnome org>]

The branch 'wip/ebassi/legacy-gl' 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:

  54700c1... x11: Create legacy GLX contexts
  72cec88... Control legacy GL context via environment variable
  06f1adc... Allow testglarea to work with legacy GL contexts
  0c975e4... docs: Improve description of gdk_gl_context_is_legacy()
  12a564d... wayland: Allow falling back to compatibility EGL contexts

Commits added to the branch:

  c547fd0... x11: Create legacy GLX contexts
  51fc793... Control legacy GL context via environment variable
  3353e76... Allow testglarea to work with legacy GL contexts
  3e6693c... docs: Improve description of gdk_gl_context_is_legacy()
  116c961... wayland: Allow falling back to compatibility EGL contexts