I fiddled around a bit and got an error about the memory manager needing to be ported to that platform. Is the error really the reason I cannot compile to DOS?
(I didn't legitimately expect it to work, just playing around)
I'd just like to second this endeavor.
I've always wanted to tinker with getting djgpp (or one of the abandonware compilers) in dosbox to work with Nim-generated C89 code, but never found the time / energy.
DOS support is the ultimate retroNerdCred! ;-)