In nroff-mode it'd be good if auto-fill-mode didn't fill when you're
entering a long directive line like

    .IP some long line going past your normal fill width ...

Almost always *roff directives have to be a single line.  I struck the
problem with a groff .URL with a long url doubled-up to both display
literally and be clickable in -Thtml.

I've been using the regexp below, which suppresses auto-fill on .IP and
the like, but continues to auto-fill the comment directives (no change)

    .\"    traditional
    .\#    groff extension
    '''    another traditional, apparently

And of course non-directive lines ("." or "'") are still auto-filled
(either ordinary text, or comments starting \" and \#).


2008-08-18  Kevin Ryde  <user42@zip.com.au>

	* textmodes/nroff-mode.el (nroff-mode): Set auto-fill-inhibit-regexp
	so as not to auto-fill on directive lines, other than comment
	directives.