4.21.4

- Add gir typelib building for libxfce4kbd-private
- clipboard-manager: Exclude krita from gtk-clipboard management
- build: Be sure to generate sub-headers before including libxfce4ui.h
- item-list-ext: hide-in-buttons attribute
- item-list-ext: gtkdoc
- item-list-ext: before/after-set-activity -> activity-changed
- item-list-ext: ellipsize by default for name
- item-list-ext: New signals
- Drop glade
- build: Fix typo in optimization level
- Translation Updates:
  Albanian, Amharic, Arabic, Armenian, Armenian (Armenia), Asturian,
  Azerbaijani, Basque, Belarusian, Bengali, Bulgarian, Catalan, Chinese
  (China), Chinese (Hong Kong), Chinese (Taiwan), Croatian, Czech,
  Danish, Dutch, Eastern Armenian, English (Australia), English (United
  Kingdom), Esperanto, Estonian, Finnish, French, Galician, Georgian,
  German, Greek, Hebrew, Hungarian, Icelandic, Indonesian, Interlingue,
  Italian, Japanese, Kazakh, Korean, Latvian, Lithuanian, Malay,
  Norwegian Bokmål, Norwegian Nynorsk, Occitan (post 1500), Persian
  (Iran), Polish, Portuguese, Portuguese (Brazil), Romanian, Russian,
  Serbian, Slovak, Slovenian, Spanish, Swedish, Telugu, Thai, Turkish,
  Ukrainian, Urdu, Urdu (Pakistan), Uyghur, Venetian, Vietnamese, Welsh