[tex-live] xdvi on mac os

[Richard Koch]

JF asked "but will XQuartz 2.7.9 be backward compatible with
xdvi binaries of bygone years?".

I'm in San Francisco for the opera: Carmen last night, Don Carlos
tonight, Jenufu tomorrow.

The answer is that you cannot have everything (and thus the
answer is NO). TeX Live protects itself against library changes
by including its own copy of most important libraries. Thus if
you run TeX Live 2014, you are running binaries compiled with
an older version of libpng, or popler, or icu, but you are
also running older versions of these libraries. One exception
is common libraries like the standard C library, but these are
usually upward compatible. Mac 64 bit binaries, for example, were
compiled on Snow Leopard.

X11 is a special case because it is a fundamental library on Linux
machines, so TeX Live doesn't contain it.

You can install the latest XQuartz on Snow Leopard and above, 
so all our machines can run the latest binaries.

But do older binaries of xdvi run on these machines after
they have been updated to the latest XQuartz. Luckily,
my traveling portable has the 2012, 2013, and 2014 binaries, 
so I can test, and the answer is NO.

Usually users need xdvi for "isolated checks", and it is easy
enough to switch to TeXLive 2016 temporarily and make that check.

Since this email is essentially a piece of bad news, let me end
with some good news. I am running MacTeX-2016 and TeX Live 2016,
and doing these checks, in Sierra.

Dick Koch