Fall back to looking for the MPI command in the putative Conda binary…

… directory

If `$CONDA_PREFIX/bin` is not in the `PATH`, then the putative Conda binary
directory is the same as the directory the Khiops `MODL[_openmpi|mpich]` binary
is situated in.

closes #476

packaging/linux/common/khiops_env/khiops_env.in

@@ -84,8 +84,15 @@ if command -v mpiexec &>/dev/null; then
     KHIOPS_MPI_ERROR=""
     KHIOPS_MPI_COMMAND="$(type -P mpiexec) $MPI_EXTRA_FLAGS @KHIOPS_MPI_EXTRA_FLAG@ @MPIEXEC_NUMPROC_FLAG@ $KHIOPS_PROC_NUMBER"
 else
-    KHIOPS_MPI_ERROR="We didn't find mpiexec in the regular path. Parallel computation is unavailable: Khiops is launched in serial"
-    KHIOPS_MPI_COMMAND=""
+    _MPIEXEC=@KHIOPS_PATH@mpiexec
+    if command -v $_MPIEXEC &>/dev/null; then
+        KHIOPS_MPI_ERROR=""
+        KHIOPS_MPI_COMMAND="$_MPIEXEC $MPI_EXTRA_FLAGS @KHIOPS_MPI_EXTRA_FLAG@ @MPIEXEC_NUMPROC_FLAG@ $KHIOPS_PROC_NUMBER"
+    else
+        KHIOPS_MPI_ERROR="We didn't find mpiexec in the expected paths. Parallel computation is unavailable: Khiops is launched in serial"
+        KHIOPS_MPI_COMMAND=""
+    fi
+    unset _MPIEXEC
 fi
 
 # without more than 2 procs, we use the serial khiops