Turns out there's a pre-built (but slightly old) Emacs binary
built for 1.3.0 in
ftp.netbsd.org://ftp/pub/NetBSD/packages/1.3/mips/All/emacs20-2.tgz
This doen't unexec, so it takes a while to start up, but i've been
using it for ages.
Now that we have a fully-functional gdb, would anyone else like to
take on finishing Terry's unexec?