To generate fontconfig.vapi:

vapigen --library fontconfig /path/to/fontconfig-2.0.gir

To generate freetype2.vapi:

vapigen --library freetype2 /path/to/freetype2-2.0.gir

To generate pangoft2.vapi:

vapigen --library pangoft2 /path/to/PangoFT2-1.0.gir

To generate gnome-desktop-3.0.vapi:

vapigen --pkg gio-2.0 --pkg gtk+-3.0 --library gnome-desktop-3.0 /path/to/GnomeDesktop-3.0.gir

To generate gnome-desktop-3.0.vapi docs:

valadoc --vapidir /path/to/vapi/dir --pkg gdk-3.0 -o gnome-desktop-3.0 gnome-desktop-3.0.vapi

To generate libxklavier.vapi:

vapigen --metadatadir . --pkg x11 --library libxklavier /path/to/Xkl-1.0.gir

To generate libxklavier.vapi docs:

valadoc --vapidir /path/to/vapi/dir --pkg x11 -o libxklavier libxklavier.vapi

To generate libgnomekbd.vapi:

vapigen --metadatadir . --pkg gtk+-3.0 --library libgnomekbd /path/to/Gkbd-3.0.gir

To generate libgnomekbd.vapi docs:

valadoc --metadatadir . --vapidir /path/to/vapi/dir --pkg gtk+-3.0 --pkg Xkl-1.0 -o libgnomekbd libgnomekbd.vapi

To generate ibus-1.0.vapi docs:

valadoc --vapidir /path/to/vapi/dir -o ibus-1.0 /path/to/ibus-1.0.vapi

To generate libbamf3.vapi:

vapigen --library libbamf3 /path/to/Bamf-3.gir