Bug#1112503: openmpi: non-intel arches fail looking for x86_64 compiler

[Drew Parsons]

Source: openmpi
Version: 5.0.8-5
Severity: serious
Justification: debci

Looks like x86_64 got hard-coded somewhere in the last patch.

arm64 and other non-intel arches are failing openmpi C compiler tests
with the error

 49s autopkgtest [22:49:05]: test compile-run-mpicc: [-----------------------
 49s --------------------------------------------------------------------------
 49s The Open MPI wrapper compiler was unable to find the specified compiler
 49s x86_64-linux-gnu-gcc in your PATH.
 49s 
 49s Note that this compiler was either specified at configure time or in
 49s one of several possible environment variables.
 49s --------------------------------------------------------------------------
 50s autopkgtest [22:49:06]: test compile-run-mpicc: -----------------------]
 50s autopkgtest [22:49:06]: test compile-run-mpicc:  - - - - - - - - - - results - - - - - - - - - -
 50s compile-run-mpicc    FAIL non-zero exit status 1