Adding the "links" text mode web browser to the base system

[Alan Barrett <apb%cequrux.com@localhost>]

The NetBSD base system includes HTML versions of man pages, and
several other HTML files.  However, it does not include an application
capable of displaying such files.

I would like to add the "links" text mode web browser to the NetBSD
base system.  It has a GPLv2 licence, and I would add it under
src/external/gpl2/links, and make it install as /usr/bin/links.
A MKLINKS build-time option could prevent building it.  The i386
executable is 1064887 bytes unstripped, 1009916 bytes stripped.

In addition to its use for displaying documentation that is
distributed with the system, a web browser has obvious uses for
browsing the web.  As non-graphical browsers go, links seems to
work reasonably well.

--apb (Alan Barrett)