[bug#27850] gnu: mpi: openmpi: Don't enable thread-multiple

[Dave Love <fx@gnu.org>]

Ludovic Courtès <ludovic.courtes@inria.fr> writes:

>> diff --git a/gnu/packages/mpi.scm b/gnu/packages/mpi.scm
>> index 54fdd35ad..678d7dd88 100644
>> --- a/gnu/packages/mpi.scm
>> +++ b/gnu/packages/mpi.scm
>> @@ -130,10 +130,10 @@ bind processes, and much more.")
>>      (native-inputs
>>       `(("pkg-config" ,pkg-config)
>>         ("perl" ,perl)))
>> +    (outputs '("out" "lib" "debug"))
>
> This should go to a separate patch.

Yes, that's a mistake, and I'd actually forgotten I'd sent the patch.
(I detest git.)  I have a new version to send, which I'll edit for the
nitpicks.

>>      (arguments
>>       `(#:configure-flags `("--enable-static"
>>  
>> -                           "--enable-mpi-thread-multiple"
>
> Should we upgrade our openmpi package instead of doing this?

I don't know whether they've fixed all the breakage I knew about in
OMPI 2 or whether there's still any penalty from thread-multiple.  1.10
seems fairly safe, but I don't have strong opinions if people think 2 is
solid.  Apart from ABI incompatibility, I assume it has the usual
incompatibilities at the mpirun/MCA level, and that they aren't well
documented.