As I know, there are also bibg applications ported from DOS to linux
(like
doom), I thoughtm that would be easy - just start a cross compiler,
then fix
some issues, ready. But I believe, it is not that easy, I suppose, this
is a
lot lot lot work. And as far as I understood, code from DOS C is far
from
similar to Linux C.
The opposite is in fact true: the C language with its core library is
highly standardized and portable across all platforms. There probably is
no "more portable" computer language in existence.
Implementation-specific libraries, however, are usually not portable,
hence applications using these libraries must be adapted to the target
system. And that bit is not "some issues" -- it's the real work.