Comment #10 on issue 2872 by [email protected]: Patch: Provide define-session and define-session-public commands
http://code.google.com/p/lilypond/issues/detail?id=2872
Ah, ok. Changing (define-public supported-clefs ... into (define-session-public supported-clefs _not_ changing (define-public (add-new-clef ... does the trick.
