>>174
3 のこの部分じゃないの？
However, as a special exception, the source code distributed need not include anything that is normally distributed (in either source or binary form) with the major components (compiler, kernel, and so on) of the operating system on which the executable runs, unless that component itself accompanies the executable.
これは簡単に言うとGPLなプログラムを配布する時にOSまでは含まなくてもいいよって話
そうでないと例えばWindows用のプログラムは配布できなくなるから
OS自体がGPLなら当然ソース提供は必要だよ