- make adding PMIx library to compile time based on the result of
finding PMIx support. This is required eg if compiling rocSHMEM with ompi
4.0/4.1, which do not have a built-in PMIx version.
- when setting USE_EXTERNAL_MPI=OFF which ensures that we do not
check for external MPI libraries (even if one would be available).
[ROCm/rocshmem commit: ed957302d4]
Edgar Gabriel
feab645795