Stallman on GCC, LLVM, and copyleft

it's useful for using them in plugins too, otherwise you'll have to deal with quite a few ifdefs if you use the changed functions/etc (which happens to be true for the PaX plugins hence the motivation for this compat header, that of course means that it's not exhaustive either, so don't rely on it as as a reference too much, and yes, patches are welcome ;). of course there're ifdefs you can't avoid, mostly due to the c++ conversion going on since 4.7 but that mostly affects pass registration and not actual plugin code (ok, the VEC_* vs. vec_* stuff is still there but even that could be abstracted away to an extent).