When cross building the gir files (*.gir, *.typelib) are installed
at ${DESTDIR}/usr/${XBPS_CROROSS_TRIPLET}/usr/* while they need to
be at ${DESTDIR}/usr/*
This hook is a temporary workaround until we can fix the cross gir
install to not insert the (as it seems) host's ${DESTDIR} into the
target's destination path.
Remove the temporary hack in polkit which is now handled by the hook.
