PJ: delete temporary *.LBC files
PJ: delete *.LST from source control
PJ: delete *.ERR from source control
PJ: delete temporary file FOO
PJ: delete AA.CFG from source tree
PJ: work around dosbox choice command

Judging by the documentation, the original authors had a CHOICE.EXE
DOSBox also implements a CHOICE command but incorrectly parses "[y/n]"
in the message as an illegal switch "/n]".  We just delete that part of
the message as it is redundant anyway.
PJ: replace wcc386p by wcc386

For unknown reasons, wcc386p (or rather, the Phar Lap extender) crashes
when invoked from Borland/TurboC make.  Therefore replace it everywhere
by the real mode version, wcc386.  Unforunately, wcc386 runs out of
memory very easily.

Obviously the original authors were able to use wcc386p but I have
had no success with Watcom C version 8.5a, in QEMU and DOSBox.
PJ: reduce memory usage of wcc386

Disable optimisations and debugging information to avoid wcc386 running
out of memory.  This is sufficient for many modules but not all,
for which we will require wcc386p.
PJ: use wcc386p, wmake in main directory

wcc386 runs out of memory while compiling many modules in the main
directory, so we want to use wcc386p instead.  As mentioned before,
wcc386p always fails for me when called from tcmake so switch to wmake
(Watcom make) for the main directory.  wmake requires slightly different
makefile syntax so convert the file.

Though it would be nice to use a single make program throughout,
converting all makefiles to wmake syntax would be tedious.
Furthermore, Borland make syntax is closer to Unix/GNU make syntax
which might be useful for the future.