From what I can tell, they have structured it in a way that it's a violation in spirit, but not in letter. They don't link to GCC code directly; instead they o

From what I can tell, they have structured it in a way that it's a violation in spirit, but not in letter. They don't link to GCC code directly; instead they output the intermediate representation and execute a standalone binary to finish processing the IR. They offer source code for all their GCC modifications, but carefully work around the GPL to accomplish the same thing.