Source: hypre Followup-For: Bug #1139536 mpi.h comes from MPI (libopenmpi-dev), and hypre was previously able to find it using the standard mpi configuration methods.
The problem is reproducible at https://tests.reproducible-builds.org/debian/rb-pkg/unstable/amd64/hypre.html I might have though that an openmpi update introduced a bug that needs to be fixed, but it has no recent updates. We'll have to dig a little to understand what's changed.
