Disclaimer: I am not a lawyer. This is not legal advise.

Another option would be RPC - remote procedure call.

Similar to Corion's stub/shim library suggestion, but adds an "ether gap" between your program and the library.

As best I know, a GPL'd webserver doesn't "infect" webbrowsers with the GPL. Similarly, wrapping the GPL'd library in a RPC server should not infect the RPC clients using it (though the server itself would be infected).

Of course, always best to consult an actual IP lawyer. In this case, preferably one with open source experience.