Problem with Eshell and grep.

[Matt Hodges]

In GNU Emacs 21.3.50.9 (i686-pc-linux-gnu, GTK+ Version 2.4.10)
 of 2004-10-11 on dugong
configured using `configure '--with-gtk''

After starting Eshell, M-x grep modifies the global value of
process-environment if called from an Eshell buffer, initially
prepending "GREP_COLOR=01;41" and "GREP_OPTIONS= --color=always", and
adding another " --color=always" to GREP_OPTIONS for each subsequent
call to grep. (To reproduce this, it is sufficient to eval
(make-local-variable 'process-environment) and then M-x grep from the
same buffer.)

The interaction between compilation-start and grep-process-setup
doesn't take into account that process-environment may be buffer
local. The current buffer changes between compilation-start and
grep-process-setup, and the global binding of process-environment gets
modified in the latter function.

Also, the binding of compilation-process-setup-function in eshell-grep
may now be obsolete.

Thanks,

Matt