Since r171598 gir files are installed under $datadir/webkitgtk-4.0/gir-1.0/. The gir files should installed in $datadir/gir-1.0/ together with all other gir files. We don't need to install introspection files in a versioned directory because their filenames already contain the binary version. But before r171598, the files were only installed to the right directory if the gobject-instrospection pkg-config file was in the same prefix than the one we wanted to install, because the gir and typelibs directories were extracted from the pkg-config file. We should define INTROSPECTION_INSTALL_GIRDIR and INTROSPECTION_INSTALL_TYPELIBDIR in OptionsGTK.cmake based on $datadir and $libdir like we do in the autotools build (grep for girdir and typelibsdir in GNUmakefile.am)
See also https://bugzilla.gnome.org/show_bug.cgi?id=734327
Created attachment 236585 [details]
Comment on attachment 236585 [details]
Yeah, I think that makes sense.
Committed r172583: <http://trac.webkit.org/changeset/172583>