JohannesEbke/a4 — pull request #127 by pwaller (2012-05-07 15:37:33+00:00)
Title: a4io/output_stream: Bail out if we've already written a FileDescriptor w...

...ith a given name, but the previous one's pointer is different

I'm not sure if this might bail out in some places where it shouldn't. Please test carefully before passing on to others.