AMD Radeon GCN Offloading Support For OpenMP/OpenACC On The Way For GCC 10

Merged for the GCC 9 compiler release that launched earlier this year was the preliminary AMD Radeon "GCN" GPU compiler back-end. In that initial release it wasn't particularly useful as the GPU offloading bits for the popular programming APIs/models wasn't supported so for now could just run some basic single-threaded programs. But now those interesting GPU offloading bits are pending for GCC 10...