I am trying to get a set of nine *.c files (and nine related *.h files) to compile under Windows.
The code was originally designed in Linux to take command line argu
You are correct. getopt() is POSIX, not Windows, you would generally have to re-write all command-line argument parsing code.
Fortunately, there is a project, Xgetopt, that is meant for Windows/MFC classes.
http://www.codeproject.com/Articles/1940/XGetopt-A-Unix-compatible-getopt-for-MFC-and-Win32
If you can get this working in your project, it should save you a fair bit of coding and prevent you from having to rework all parsing.
Additionally, it comes with a nice GUI-enabled demo app that you should find helpful.
Good luck!