[tlbuild] LuaMetaTeX for TeX Live

[Karl Berry]

cmake should not be a hard requirement for the TL build. I guess it
could be ok if cmake availability is detected, and skip lmtx if it is
not, but that's yet another level of complication.

    > That is, nothing more needs to happen at TL installation time? That
    > would be good.
    No.

Excellent. In that case, it should be entirely straightforward to import
the binaries.

    The only thing that's needed is of course a package for the new engine
    and appropriate dependencies.

Yep. No problem.

Thanks for the other info. -k