Some updates for djgpp/MS-DOS.

main.c; cleanup, potential outfile overrun fixed. Use delay() and
not poll(). Prevent CRT globbing our cmd-line.

common.dj; Must add '-I../lib' to CFLAGS (damn!).

See Packages/DOS/REAME for the culpits.

I also added dumping of env-vars to memdump. I think it's handy to
see the details, but feel free to drop it.

--gv