Update gtk3 to 3.6.4

Changes in 3.6.4:
* Bug fixes:
 691186 stylecontext: Make font hack not crash

Changes in 3.6.3:
* The Wayland backend works with Wayland 1.0.0 now
* Bug fixes:
 132333 Can't add a palette to the dialog of a color button
 371034 Doc for gtk_file_chooser_get_filename: Is the resulting...
 548793 funny pattern for iterating GtkTreeModel
 577806 gtk_file_chooser_add_shortcut_folder adds duplicates of...
 626499 GtkClipboard unnotified on change of OS X pasteboard owner
 668239 texts disappear when notebook switch page at zh_CN locate!
 672193 windows (including menus) shown multiple times don't ge...
 677339 GTK+ 3 documentation wrong about GtkWidget scroll-event...
 683072 Print dialog shows cryptic status message and displays ...
 687065 InstallableOptions is not filtered in cups backend
 687816 GtkTreeView does not draw correctly since commit aaedc7b6
 688710 [PATCH] Splash screens shouldn't stay on top of all app...
 688884 Typo in gtk_tree_view_set_tooltip_column documentation
 689235 Broken function declarations corrupt the stack on windows
 690266 Freeze with F10/Shift-F10 on submenus
        Win32: Avoid infinite recursion in the ime input module
        Quartz: Fixes for splashscreen and tooltip windows
* Translation updates: Dutch German Gujarati Tamil Uyghur
Updated x11/gtk3 to 3.6.4