GNU atomics

Makefile.kokkos

containers/src/Kokkos_UnorderedMap.hpp

core/perf_test/test_atomic.cpp

core/src/Kokkos_Atomic.hpp

core/src/Kokkos_Complex.hpp

core/src/Kokkos_MemoryOrder.hpp

core/src/Kokkos_Pair.hpp

core/src/impl/Kokkos_Atomic_Deprecated.hpp

core/src/impl/Kokkos_Atomic_GNU.hpp

core/src/impl/Kokkos_Atomic_Ops.hpp

core/src/impl/Kokkos_Atomic_View.hpp

core/src/impl/Kokkos_HostSpace.cpp

core/unit_test/TestAtomic.hpp