[gtk] (7 commits) ...Merge branch 'matthiasc/for-master' into 'master'

[Matthias Clasen <matthiasc src gnome org>]

Summary of changes:

  c835df5... docs: Add more details to the migration guide (*)
  e7aa103... gtk-demo: Ellipsize columns in the characters demo (*)
  eb64729... build: Require sysprof 3.38.0 (*)
  6a0704a... window: Be more careful when looking for focus (*)
  115ed00... Send focus events to the root (*)
  8fcd4ac... gtk-demo: Keep undisplayable resources out of view (*)
  758675f... Merge branch 'matthiasc/for-master' into 'master'

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