Question: I have googled and looked all over, but can't find it ANYWHERE. Anyone know where to get it?

Answer: 
OK. After a little research on the documentation for this, I believe the library you're looking for is part of the WinAVR-GCC Toolkit, the static library kit for CEENBoT-API, and a few other things. According to the [links](http://www.ceen.unomaha.edu/CEENBoT/API/CEENBoT-API_GettingStarted%28Rev1.07%29.pdf) at UnOmaha, there are a variety of things you need to program those little gems. But the configuration of what I believe you're looking for is on page 11 of the linked PDF. There is a fairly nice walkthrough of configuring the project.

These robots are effectively programmed using a cross-compiler, and configuring them is always a fun agenda. I wish you the best of luck. (and now you made me want to go out and buy one as soon as I clear it with my wife, cuz these things look damn-cool).
math library is part of C standard library. It should be provided with compiler.