[tlbuild] mpost this time

[Karl Berry]

Sorry again, but for those unlucky enough to be following the tex-live
list, you'll know that Werner (Lemberg) reported a crash in mpost for
(Lilypond-related) files that always worked before.  Dependent on how
fussy your system's malloc/free are, but anyway.  Taco committed a
workaround.  mpost is the only thing that's modified.

One more time.  I really really really hope this is the last one.
I don't have anything pending.  Of course, I didn't know this one
was pending until yesterday :(.

Still just reporting the (bad) news,
karl