HIP: Default CMAKE_HIP_ARCHITECTURES when rocm_agent_enumerator fails
Currently we default
CMAKE_HIP_ARCHITECTURES based on
rocm_agent_enumerator, but if the enumeration fails, we fall back to parsing
-target-cpu flags from the compiler identification step's output. This makes results unpredictable for projects, and currently we provide no way to distinguish the cases.
This was raised originally on discourse.