Comment #3 on issue 2591 by [email protected]: NR: repeat slurs and glissando workaround
http://code.google.com/p/lilypond/issues/detail?id=2591
As I mentioned before: it seems to me like using the kind of slur/tie that would be employed after a line break would seem like the right thing to use here, so it might make sense if the repeat constructs siphoned off unfinished spanners at the start of the first alternative and replicated them as post-break into every other alternative.
