configure: prevent glade support being enabled when --without-glade is used
configure: prevent glade support being enabled when --without-glade is used

http://bugzilla.clutter-project.org/show_bug.cgi?id=2635

pwithnall/mx,jonnylamb/mx,jonnylamb/mx,clutter-project/mx,clutter-project/mx,jonnylamb/mx,jonnylamb/mx,clutter-project/mx,clutter-project/mx,pwithnall/mx,pwithnall/mx,pwithnall/mx