Bug#1068318: code-saturne: Build against mpich for MPI on 32-bit systems

[Emilio Pozuelo Monfort]

Control: severity -1 serious

On Wed, 03 Apr 2024 13:24:26 +0100 Alastair McKinstry <mckinstry at debian.org> wrote:
> Source: code-saturne
> Version: 6.0.2-2
> Severity: normal
> X-Debbugs-Cc: debian-hpc at lists.debian.org
> 
> As of openmpi 5, OpenMPI will no longer build on 32-bit systems.
> So mpi-defaults will point to MPICH on 32-bit systems after the MPI transition.
> Please enable code-saturne to build on systems where OpenMPI is not present.

openmpi 5 is in unstable now, and no longer builds on 32 bit architectures.

The easiest way to solve this is to build-depend on mpi-default-dev (which 
code-saturne already does, at least in experimental) and drop the 
build-dependency on libopenmpi-dev, relying on mpi-default-dev to pull 
libopenmpi-dev or libmpich-dev as appropriate.

Cheers,
Emilio