GCC 8/9 Land Fix For "-march=native" Tuning On Modern Intel CPUs

The other day we reported on a GCC 8 regression where Skylake and newer CPUs with "-march=native" haven't been performance as optimally as they should be. Fortunately, that patch was quickly landed into the GCC SVN/Git code for GCC 9 as well as back-ported to GCC 8...