The GNU Make manual says: "$(sort list) Sorts the words of list in lexical order, removing duplicate words. The output is a list of words separated by single spaces."
Created attachment 585034 [details] [diff] [review] pymake sort function should remove duplicates. Pretty simple patch, all tests pass with this applied.
http://hg.mozilla.org/users/bsmedberg_mozilla.com/pymake/rev/0fdfecdb0567 I'll push to b-s soon.