bug#1279: color output from external programs not working by default in eshell

[Stefan Monnier <monnier@iro.umontreal.ca>]

> When running eshell, using an external program that outputs in color results 
> in the raw terminal escape codes being displayed. For example,
> ~ $ yaourt -Ss emacs
> ^[[3m^[[1;32mextra/^[[0m^[[0m^[[1memacs ^[[1;32m22.3-1 
> ^[[7m^[[1;33m[installed]^[[0m ^[[1;34m^[[0m
> ^[[3m     The Emacs Editor^[[0m
> ^[[3m^[[1;32mextra/^[[0m^[[0m^[[1msnd ^[[1;32m10.1-1^[[0m ^[[1;34m^[[0m
> ^[[3m     Snd is the emacs of sound editor^[[0m
> ^[[3m^[[1;32mextra/^[[0m^[[0m^[[1mtexmacs ^[[1;32m1.0.6.14-1^[[0m 
> ^[[1;34m^[[0m
> ^[[3m     GNU TeXmacs is a free scientific text editor, which was both 
> inspired by TeX^[[0m
> ...

FWIW, I consider it a bug for such programs to output ANSI escape
sequences for color unless they have some concrete evidence that the
terminal to which they talk does understand those escape sequences.

What does $TERM say in your shell?  Is this terminal type known to
support color?  If so, specifying such a terminal type is an error and
we try and figure out where it comes from so we can fix it.


        Stefan