Seems to require Win32 (Digital Mars C/C++ Compiler Version 8.57). Is there a version of the C compiler than can run on FreeDOS or MS-DOS ?

Not any more. The Win32 one functions as a cross compiler. The compiler is a little large for MS-DOS' memory.

	▲	jabl 4 days ago \| parent [-]
		AFAIU it was just (some versions of?) DOS/4GW that had a 64MB limit. Some other DOS extenders, in particular the open source DOS/32A, allow using the full 4GB virtual address space.