ROCm: Merge from rocm-hackathon2

[chipfreitag]

Got MDRange reduce working, will push commits soon.

With my unit_test/standalone builds of the reduction tests, the KOKKOS_IMPL_ROCM_CLANG_WORKAROUND macro is never getting defined, because no ROCm include files are brought in before the range(point_type()...) calls are compiled. This causes the "no matching constructor" errors.

I end up just commenting out the ifdef in Kokkos_Arrray, but this is obviously not acceptable. I haven't found a convenient global way (short of defining at make time) to get Kokkos_ROCm_Config.hpp included so that the macro is defined.

My build command looks like:
make -f /home/chipf/kokkos-kh/core/unit_test/standalone/Makefile KOKKOS_ARCH=SNB,Vega KOKKOS_DEVICES=ROCm CXX=/opt/rocm/hcc/bin/clang++ -j 8

[ibaned]

@chipfreitag we've opened a pull request to do this, we'll merge it in after the current release.

[crtrott]

We can define this KOKKOS_IMPL_ROCM_CLANG_WORKAROUND in the Makefile.kokkos so its gonna be part of the KokkosCore_config.h which is always included first.