2009-03-05 Luchezar Georgiev wrote in newsgroup c.o.m.4

4DOS builds only with the Microsoft C 8.0 (a.k.a. Visual C++ 1.x) compiler. 
Neither Borland C, nor the Walter Bright's compilers (Datalight C / Zortech 
/ Symantec / Digital Mars) are supported. Even Watcom can't fully build it.

There is a batch file called MKDOS which you need to run. See my web site 
for the exact steps to do. As to setting up the compiler, it is enough to 
extract the VC152.EXE in e.g. C:\VC, and adjust the PATH, INCLUDE and LIB 
environment variables. For example:

PATH=C:\VC\BIN;%PATH%
SET INCLUDE=C:\VC\INCLUDE
SET LIB=C:\VC\LIB

But you don't need to set the variables in your environment. Only in MSC7.BTM,
as described on my site. In short, all the information is already on my site. 
Read it and do it. That's all.