Log Message:
gtk3+: update to 3.24.12.

Overview of Changes in GTK+ 3.24.12
===================================

* file chooser: allow sorting by file type

* dnd: fix pointer offsets under X11 and Wayland

* broadway: Fix a font problem

* mir Drop this backend

* printing: Get PPD from original host if needed

* a11y: Fix interference with clutter a11y impl

* Translation updates:
 Brazilian Portuguese
 Czech
 Danish
 Dutch
 Italian
 Greek
 Lithuanian
 Norwegian Bokmål
 Polish
 Romanian
 Slovenian
 Spanish
 Turkish