python312Packages.mpi4py: convert dependency mpi to python module (#399291)

pkgs/development/python-modules/mpi4py/default.nix

@@ -5,6 +5,7 @@
   cython,
   setuptools,
   mpi,
+  toPythonModule,
   pytestCheckHook,
   mpiCheckPhaseHook,
 }:
@@ -31,7 +32,9 @@ buildPythonPackage rec {
   ];
 
   dependencies = [
-    mpi
+    # Use toPythonModule so that also the mpi executables will be propagated to
+    # generated Python environment.
+    (toPythonModule mpi)
   ];
 
   pythonImportsCheck = [ "mpi4py" ];