Fix slow compilation via processxml

The compilation was very slow (days) with some linux and gcc versions:
- Mandriva 2010.0 64bits: gcc version 4.4.1.
- CentOS 5.5 64bits: gcc version 4.4.0.
This change fixed the problem. See issue #0014821.

Change-Id: I4b54f17140a56ae22b8e1af8532723e7c8a755b0
Merge topic 'compilation_issue_processxml' into next

245c75c8 Fix slow compilation via processxml
mpi4py: remove

It is now included in VTK.

Change-Id: I6dd18aef6239f0910633a702128c3d3a2c2fd479
Merge topic 'remove-mpi4py' into next

9ae2beb3 mpi4py: remove