Forked from https://blackhat.hepforge.org/ and repaired.
The BlackHat library implements on-shell methods for one-loop amplitudes numerically (arXiv:0912.4927).
But the original project has not been updated for a long time, and it cannot compile normally under modern GCC. This project patched the last version of the BlackHat code so that it can be compiled normally under modern GCC.
./build [install_path]