[tex-live] gregorio program in shell_escape_commands

[Karl Berry]

Hello TeX Live folk,

As I mentioned in the pretest news
(http://tug.org/texlive/pretest.html), and as some of you may have seen
on this list a while ago, Elie (Roux) requested adding the gregorio
utility program to shell_escape_commands.  It is part of their
gregoriotex package (http://ctan.org/pkg/gregoriotex) for typesetting
Gregorian chant.

Issues such as memory overruns, checking return values, running
valgrind, etc, have been dealt with.  The program should pay attention
to kpathsea texmf.cnf paranoia settings and (in the TL binary) not call
out to external programs.  Here is a description of some of the work and
research:
  https://github.com/gregorio-project/gregorio/issues/697

I couldn't find anything problematic in the current code, so I've gone
ahead and added it to shell_escape_commands for the pretest.
(Thanks for all the hard work, Elie, Henry, and friends.)

Any further review or testing would be all to the good, of course.
Upstream repository:
https://github.com/gregorio-project/gregorio

Sources in TL:
http://tug.org/svn/texlive/trunk/Build/source/texk/gregorio/gregorio-src/

Thanks,
Karl

P.S. This is the first program added to shell_escape_commands since we
invented it a few years ago.  For those who may not be familiar with it,
the idea is to allow TeX programs to execute these programs (and only
these programs) even when --shell-escape has not been enabled; it's the
list allowed by --shell-restricted, which is enabled *by default*, due
to shell_escape=p in texmf.cnf.

Since I'm here, for the record, the full list is, as of right now:
shell_escape_commands = \
bibtex,bibtex8,\
extractbb,\
gregorio,\
kpsewhich,\
makeindex,\
mpost,\
repstopdf,\