[jrockway]

A library's header file is included verbatim into your file by the compiler, as is the library file by the linker. When you copy-and-paste something into your own work, copyright covers the copying.

One technicality is that until you compile the program, no copying is taking place, so the GPL can't apply to source code. The only argument against that I see is that you're intending for the copy to take place, which is as good as the copy actually taking place. But I have no idea. (OTOH, not many people try to avoid the GPL when sharing their source code anyway.)

If you have a billion-dollar idea that depends on the GPL working, you should probably hire a very good lawyer to advise you.