Fixed by b4787e71aca75392f394a127a7df537a0a016b04. Ludo’.
- bug#22131: gtk-doc fails to build on all platforms Mark H Weaver
- bug#22131: gtk-doc fails to build on all platforms Efraim Flashner
- bug#22131: gtk-doc fails to build on all platfor... Ludovic Courtès
