Everything on the internet everywhere says that the error is caused by linking with gcc instead of g++, however I can prove I am linking with g++ AND that -lstdc++ is even in the command line: https://gist.github.com/LB--/6545149
Any idea what is causing this? The internet doesn't seem to have had this problem before.
Ah, then you are probably out of luck. The 64-bit MinGW cannot use the dw2 and has some fudges for exception handling anyway. I don't know what stuff Lavavej has done to MinGW, but I suspect it is the source of the problem.
You might want to email him and ask about the error. At the very least, he can probably give you the technical information you need to compile the offending library with the same options he used when compiling everything.