grep feature request: show column numbers

[Martin Pool]

It would be nice if GNU grep had an option to show the column number
of the start of the first match on each line, so that emacs grep-mode
can put the cursor exactly on the match, not just at the start of the
line.  Something like this:

% grep -nH --column GNU /etc/issue
/etc/issue:1:8:Debian GNU/Linux 3.1 \n \l

Combined with something like this: 

(setq grep-regexp-alist 
'(("\\([a-zA-Z]?:?[^:(\t\n]+\\):\\([0-9]+\\):\\([0-9]+\\)" 1 2 3)))

(I feel like this must have been requested before, but I can't find
any reference to it.)

-- 
Martin