use PATH environment variable to search for libraries and include files on windows with mingw

I don't see any obvious way to make bjam look in my PATH environment variable on windows (using gcc) when trying to locate header files and such. Is this possible? I have a directory "C:\c_libs" , which underneath I have two subfolders: "include" and "lib". I would like to modify user-config.jam (or if there is a more appropriate file to modify, please suggest) such that all my projects will always have access to the files in these folders without having to explictly reference these folders in each project's Jamroot file. Right now those folders are in my path environment variable, but I am open to the idea of creating explicity environment variables for each of those folders if that makes the task easier. But either way, I don't know how to do it. I banged my head against the keyboard for a few hours, and that didn't help.

Any assistance is greatly appreciated. Thanks,

- Matt