hdf5

Merge pull request #1958 in HDFFV/hdf5 from ~JAKE.SMITH/hdf5:develop to develop

* commit 'cab37f63144fd24d1ff39359e3d47a2c16198633':
  Move function-scope macro definition to file-scope.
  Refactor external file addition loop to static function.
  fix declaring variable in for statement