Clang's Competition For GCC On Intel Haswell

For many of the SciMark tests, the performance was close to the same between compilers.

Where LLVM Clang sped ahead with SciMark2 was in the Dense LU Matrix Factorization and Jacobi Successive Over-Relaxation cases where its performance was much better than the GNU Compiler Collection.

Just to point out that LLVM Clang doesn't yet have mainline OpenMP support, which limits its abilities in a number of scientific benchmarks.