[gtk] (6 commits) Non-fast-forward update to branch wip/chergert/gdk-macos-gl-renderer

[Christian Hergert <chergert src gnome org>]

The branch 'wip/chergert/gdk-macos-gl-renderer' 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:

  4cfad21... macos: be resilient to NULL GdkGLContext
  b593e25... macos: move setNeedsDisplay:BOOL to cairo implementation
  362c9cf... macos: remove incomplete GL layer
  655b353... glsl: tweak preamble to work on Apple glsl compiler
  0076e4c... macos: add basic GL view and wire up GL context to use it
  4dfbb34... macos: use shared data GL context
  590a7c4... gl: hold ref to previous context when replacing
  7499fc8... macos: create NSOpenGLPixelFormat once
  5c5bcb7... macos: wip on making GL renderer more compliant
  6052aea... macos: remove layer scaling when resizing
  e5989ff... macos: reduce renderer requirements
  5938e50... macos: chainup end_frame before flushing buffer
  bfc2a3e... macos: setup native window and view for accelerated GL
  b56ace5... macos: setup clip for flushBuffer
  ba1c8fe... macos: do less work to update backing surface
  c40e8e5... macos: tweak gravity during resizes
  4e69860... macos: clear current context if necessary
  66013ff... macos: use g_message() for GL info
  2d63df0... macos: remove early pixelFormat check
  4598285... macos: log requested version of Core profile
  3122d4b... macos: cleanup pixelFormat creation
  8e9fe2c... macos: provide GL driver information to debug message
  8995801... macos: avoid duplicate call and update GL context
  a9340e8... macos: restore GL context after realize
  1db0132... macos: wait for begin_frame to switch to GL view

Commits added to the branch:

  2b4dfaa... macos: move setNeedsDisplay helper to GdkMacosCairoView
  0f0c531... macos: remove unused GL layer
  50f8e1c... glsl: tweak pre-processor to support Apple GLSL compiler
  ff58297... macos: be tolerant of NULL GL context
  d8dde61... macos: tweak gravity while resizing
  6a902f3... macos: implement GL context