[gtk] (9 commits) Non-fast-forward update to branch wip/otte/for-master

[Benjamin Otte <otte src gnome org>]

The branch 'wip/otte/for-master' 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:

  dbf051a... rbtree: Simplify code
  423a973... rbtree: Simplify macros
  18b0b78... device: Handle missing axis
  6678017... icontheme: Don't crash on icon lookup failure
  abcb45d... notebook: Don't crash on drags not coming from a notebook
  c0568a0... treerbtree: Use for loops
  c197747... build: Add more useful warning flags
  a868ff5... build: Add -Wnull-dereference

Commits added to the branch:

  f6b11a5... build: Add more useful warning flags
  9fedcec... rbtree: Simplify code
  dc86c74... rbtree: Simplify macros
  a4ed6fd... device: Handle missing axis
  fdd4630... icontheme: Don't crash on icon lookup failure
  4e88d5a... notebook: Don't crash on drags not coming from a notebook
  7dce9e4... treerbtree: Use for loops
  3ab561c... icontheme: Remove unused variable
  b628ba2... build: Add -Wnull-dereference