[tlbuild] dvipdfm-x issues

[Bob Tennent]

 >|Also, if I look at the programs missing from the various builds, in
 >|the second table at
 >|
 >|	http://www.math.utah.edu/pub/texlive/
 >|
 >|it appears that
 >|
 >|	inimflua inimfluajit m-tx pmx2pdf
 >|
 >|are commonly absent, 

The m-tx and pmx2pdf scripts are absent from TL2016 because
the musixtex script itself now pre-processes .mtx and .pmx
files.

It didn't occur to me before but to avoid surprises for
current users, it might be a good idea to create symlinks
to musixtex.  

Bob T.