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it seems to be GPL incompatible.
I replaced this implementation with the libbase64 which claims to be the fastes C++ implementation. I know I know that speed doesn't matter at this point at all but I wasn't so happy with the copyright issues mentioned above (our SHA-1 implementation have the same issue but thats another topic ;)).
You can find the new implementation (or call it linking whatever) in my master.
If there is interest in this replacement I will backport it.