Here is a simple one-line-fix patch with a test. 

Except for the libraries option, other options separate using ':'. The documentation didn't seem to say much, so I wasn't sure if link_objects should be consistent with that or if it should follow libraries's example and instead allow spaces and commas for separation. This patch uses ensure_string_list as suggested, but let me know if using .split(os.pathsep) is a better idea.