GCC vs. Clang Compiler Benchmarking On Intel's Skylake CPU

Other SciMark tests tended to be very close between these competing open-source compilers.

It's with the Dense LU Matrix Factorization and Jacobi Successive Over-Relaxaton test that Clang runs out so far ahead of GCC that the SciMark composite result swings in favor of Clang.

Even with the correct OpenMP flags, LLVM Clang 3.8 didn't want to run across all the CPU cores/threads for John The Ripper.