[tlbuild] mtx and libp2c

[Bob Tennent]

Mtx is a pre-processor for pmx (itself a pre-processor for musixtex).
The source for the prepmx binary is in Pascal and it's not feasible to
translate it into C or Lua by hand. But translation using p2c produces C
code that compiles straightforwardly on several flavours of Linux, and
on SunOS and OS-X; similarly the libp2c library.

I've uploaded a tarball to CTAN. Could this be considered for inclusion
in TeXLive if pmx is accepted?

Bob T.