hdf5_ep

[svn-r27918] Brought in sync with the trunk:

r27860-27883
r27892-27916

Tested on: - h5committest
           - jam (parallel) fails with an existing, unrelated MPI config error
           - platypus fails with due to an existing, unrelated cmakehdf5 error
             where it does not recognize --enable-fortran2003.