Log Message:
gtk3: updated to 3.24.20

Overview of Changes in GTK+ 3.24.20
===================================

* GtkFileChooser:
 - Prevent selection changes after overwrite confirmation
 - Don't grab focus to the sidebar on click
 - Avoid a use-after-free in GtkFileSystemModel

* GtkEmojiChooser:
 - Remove blacklist

* GtkAboutDialog:
 - Add more licenses

* Adwaita:
 - Lower the contrast of checkboxes

* HighContrast:
 - Export the same public colors as Adwaita

* OS X:
 - Don't filter Escape in input methods

* Windows:
 - Infer font settings from system settings

* Translation updates
 Brazilian Portuguese
 Chinese
 Croatian
 French
 Japanese
 Lithuanian
 Polish
 Spanish
 Swedish
 Turkish
 Ukrainian