Since the dynlib support probably uses GPL3 headers and runtime symbols, I doubt the result can be licensed anything but GPL3, so I'm not sure what RMS would co

Since the dynlib support probably uses GPL3 headers and runtime symbols, I doubt the result can be licensed anything but GPL3, so I'm not sure what RMS would complain about. This is also the reason why LLVM's ld.gold support is a plugin IIRC, because it has to include a binutils header (/usr/include/plugin-api.h, which is weirdly generic name for such a thing to exist in /usr/include).