>=dev-libs/openmpi-5 dropped 32-bit support so dropped multilib. virtual/mpi-2.0-r8 currently still has: ``` RDEPEND="|| ( >=sys-cluster/openmpi-4.1.2[${MULTILIB_USEDEP},cxx(-)?,fortran?,romio?,threads(+)?] >=sys-cluster/mpich-3.4.3[${MULTILIB_USEDEP},cxx?,fortran?,romio?,threads?] sys-cluster/native-mpi nullmpi? ( sys-cluster/nullmpi[${MULTILIB_USEDEP},cxx(-)?,fortran(-)?,romio(-)?,threads(-)?] ) )" ``` This means that if ABI_X86="64 32" (often set globally), one can't upgrade to >=openmpi-5 and it gets skipped. If we drop multilib just from openmpi, that'll lead to confusing conflicts or solutions from Portage (where mpich may be pulled instead, etc). It seems to me we're best off by recursively dropping multilib from the MPI ecosystem, given I don't think it's particularly likely to be useful, and the flagship openmpi can't support it anymore. Objections (please no)? CC'd a few people who may have an opinion.
