[tlbuild] mtx and libp2c

[Akira Kakuto]

Dear Bob,

> 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
> 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.

Build on W32 is successful. It seems to work fine.

Thanks,
Akira