Gentoo's Bugzilla –
Attachment 592048 Details for
Bug 683896sci-visualization/paraview-5.6.0 - building against sys-cluster/openmpi-4*: .../work/ParaView-v5.6.0/VTK/ThirdParty/mpi4py/vtkmpi4py/src/mpi4py.MPI.c:14831:36: error: expected expression before ‘_Static_assert’