bug#4359: 23.1.50; ^G in M-x grep mode with git grep

[Ulrich Neumerkel]

Andreas Schwab <schwab@linux-m68k.org>
>> git grep -n -e git.describe
>> WARNING: terminal is not fully functional
>> ^Glisp/org/org.el:112:      (if (eql 0 (shell-command "git describe 
>> --abbrev=4 HEAD"))
>
>The WARNING line and the ^G is written by less.  You can work around
>that by disabling the pager or setting it to cat.

This would be an ad-hoc workaround that does not work for the next
tool.  What is needed is that the command is called such that git or
the pager doesn't think they are in an interactive environment.

I.e.,

git grep -n -e git.describe | cat

does work correctly.  Not sure how to do this in a clean manner.