There is also the case of the more liberally licensed SRC Modula-3 compiler (front end) which worked around the GPL by running GCC as a separate process and fee

There is also the case of the more liberally licensed SRC Modula-3 compiler (front end) which worked around the GPL by running GCC as a separate process and feeding it IR files. Less efficient, but effective. It's always an option if you're willing to put up with the awkwardness and inefficiency. GPL has more in common with DRM than you would think.