Comment #29 on issue 2823 by [email protected]: Patch: Fixes position of mensural c clef
http://code.google.com/p/lilypond/issues/detail?id=2823
Yes - I think we need 2 new clefs, a white one with holes in the middle of the breve-like objects, and a black one that's filled in. I think these should be called clefs.mensural.c (replacing the existing) and clefs.blackmensural.c
