I don't know KDevelop at all, but I think I can help with the following point:
Quote Originally Posted by permutations
(1) I'm getting a zillion errors complaining about every trigonometric function I call (sin(), cos(), etc.). I have math.h included at the top and this compiled fine on Windows. I also confirmed that math.h is on the Knoppix CD, though I can't begin to say if it's in the right place or if I need to do something special to point to it (evidence suggests I should). The Help file is not searchable.
You need to add '-lm' to your CC command flags. That'll pull in the math lib at link time.

Other than that, if your program is a CGI, it just deals with stdin/stdout and environment variables, so I'm not sure what you'd gain in forcing this type of project into the IDE. Just my 2 (euro) cents, of course!