All off topic discussions go here. Everything from the funny thing your cat did to your favorite tv shows. Non-programming computer questions are ok too.
DJGPP is GCC compiled to run on DOS/Windows. Cygwin is a POSIX emulation layer so you can compile programs meant for POSIX systems on Windows and use them.
Cygwin comes with GCC pre-compiled. It won't take much to convert your DJGPP OS source to something Cygwin's GCC can compile. You should probably build a crosscompiler (see GCC Cross-Compiler.)
Solar wrote:It keeps stunning me how friendly we - as a community - are towards people who start programming "their first OS" who don't even have a solid understanding of pointers, their compiler, or how a OS is structured.