Upgrade emulators/bsvc to version 2.4.3, which is the upstream latest. This
fixes many bugs in the former (ancient) version which, while it perhaps
compiled, probably didn't work. In particular, it obsoletes all of the patches
previously included with the port. This version works well enough to run an
ersatz port of Comer's Xinu teaching system that I did, based on the original
for the PDP-11.
Also add myself as the maintainer, as I am the upstream maintainer.
Incidentally, I'm also the original porter. I left my old email address at the
top of the Makefile -- that felt kind of meta.