redo build system

[PerditionC]

Currently each compiler uses its own version of make and has a slightly different path when building. This makes it difficult to make changes that don't break one of the supported compilers. Open Watcom can be used from Windows, Linux, and DOS; Borland compilers work best from DOS (or DOSBox in Windows), and GCC (ia16) works best from Linux. We need a make that works on all three OSes and can be used to simplify the build process. Gnu Make has been suggested, and perhaps using make from DJGPP would work for DOS, its natively on Linux, and there are several ports for Windows*. Alternatively we could go back to using DMAKE (if it can be found). * The windows version needs to be determined as a cygwin vs mingw vs MSVC native version could effect the compatibility of the makefiles.

[kerravon86]

pdmake is public domain and works on any C90-compliant platform and doesn't require tabs. You can get it here:

https://sourceforge.net/p/pdos/gitcode/ci/master/tree/pdmake/

[stuaxo]

I hadn't seen pdos + pdmake before, they seem to have the nice property of being currently maintained.