Package: openmpi-bin Followup-For: Bug #551708 This functionality is already available (or is now available, at openmpi 4.1.2)
The under lying C compiler can be set by environment variable OMPI_CC (more generally OMPI_value, see the man page for mpicc.openmpi). mpich has the same approach, but no man page. The online manpage at https://www.mpich.org/static/docs/latest/www1/mpicc.html reports that there is a --cc command line option to override the C compiler. But there is also an environment variable MPICH_CC, similar to the openmpi approach. More fine control can be made through profiles.
