[tex-hyphen] tamil and malayalam

[Karl Berry]

    TeX distributions like MikTeX 
    and TeX Live can decide whether the patterns for non-Western languages 
    that are only usable with xetex or luatex should be commented out by 
    default or not.

I wish we weren't going down this road of non-universally-usable
patterns at all, but maybe there's no good alternative.

Anyway, in general, the TL developers like me can't possibly guess
whether pattern foobar is only usable with xetex/luatex or not, so
saying "TeX Live can decide" isn't practical.

So let's figure out a way to mark the non-pdftex patterns so that we
(TL) have the necessary information to create a per-engine language.dat
if we go that way.  Putting them in a separate directory is what comes
to my mind.

Wdyt?