tomhudson writes "In this email from 2003, Richard Stallman says 'I've talked with our lawyer about one specific issue that you raised: that of using simple material from header files. Someone recently made the claim that including a header file always makes a derivative work. That's not the FSF's view. Our view is that just using structure definitions, typedefs, enumeration constants, macros with simple bodies, etc., is NOT enough to make a derivative work. It would take a substantial amount of code (coming from inline functions or macros with substantial bodies) to do that.' This should help end the recent FUD about the Android 'clean headers.'"