Adjusted Method by Which MPI4PY was included, separating from python proper.

CMakeLists.txt

@@ -51,6 +51,10 @@ option(XDMF_BUILD_DSM OFF)
 
 if(XDMF_BUILD_DSM)
   option(XDMF_BUILD_DSM_THREADS ON)
+  if (XDMF_WRAP_PYTHON)
+    mark_as_advanced(FORCE PYTHON_INCLUDE_MPI4PY_DIR)
+    set(PYTHON_INCLUDE_MPI4PY_DIR "" CACHE STRING "Directory containing mpi4py/mpi4py.i")
+  endif (XDMF_WRAP_PYTHON)
 endif(XDMF_BUILD_DSM)
 
 # If we are wrapping either, we need swig
@@ -67,7 +71,7 @@ if(XDMF_WRAP_PYTHON)
   find_package(PythonInterp REQUIRED)
   find_package(PythonLibs REQUIRED)
   if (XDMF_BUILD_DSM)
-    include_directories(${PYTHON_INCLUDE_DIRS} ${MPI_CXX_INCLUDE_PATH})
+    include_directories(${PYTHON_INCLUDE_DIRS} ${MPI_CXX_INCLUDE_PATH} ${PYTHON_INCLUDE_MPI4PY_DIR})
   else (XDMF_BUILD_DSM)
     include_directories(${PYTHON_INCLUDE_DIRS})
   endif (XDMF_BUILD_DSM)