[gtk/matthiasc/for-master] (14 commits) ...Add a basic clipboard test

[Matthias Clasen <matthiasc src gnome org>]

Summary of changes:

  293f2e6... demos: Fix builds against Visual Studio headers (*)
  9f1208b... Merge branch 'master.msvc' into 'master' (*)
  2df139c... gdk: Make gdk_keyval_to_unicode platform-independent (*)
  8a91d1d... Merge branch 'matthiasc/for-master' into 'master' (*)
  05736af... x11: be more verbose when glClientWaitSync behaves unexpect (*)
  fb14802... Merge branch 'wip/dont-assert-without-evidence' into 'maste (*)
  418bbb2... entrycompletion: Name the controllers (*)
  9faaa5e... Fix change notification for event controllers (*)
  692cc42... Add gtk_widget_prepend_controller (*)
  53a30ea... entry completion: Make keynav work again (*)
  c6fe881... gdk: Clarify the docs of gdk_keyval_to_unicode (*)
  1791c63... Merge branch 'fix-entry-completion' into 'master' (*)
  367d24b... Merge branch 'keyval-to-uni-fix' into 'master' (*)
  9bcf401... Add a basic clipboard test

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