[gtk+] (4 commits) Non-fast-forward update to branch wip/paint-stack-cleanup

[Jasper St. Pierre <jstpierre src gnome org>]

The branch 'wip/paint-stack-cleanup' 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:

  a9d2519... gdkwindow: Only skip alpha blending if we cleared to the ba
  a02ca0e... gdkwindow: Use bitfields for packing storage
  36f68b9... gdkwindow: Don't clear to the background automatically

Commits added to the branch:

  9036ed0... gdkwindow: Correct a signature (*)
  fd898e0... gdkwindow: Only skip alpha blending if we cleared to the ba
  0bafa6a... gdkwindow: Use bitfields for packing storage
  320dea5... gdkwindow: Don't clear to the background automatically

(*) This commit already existed in another branch; no separate mail sent