docopt takes forever

[Manishearth]

Running bindgen on current m-c takes forever.

List of arguments: https://gist.github.com/Manishearth/da907aa5efdaaeb84eaf59eab75e172a

In the past, parsing happened almost immediately, but now it's taking more than 5 minutes. Interrupting the program while it runs under a debugger always gives us a backtrace within docopt, behind the bind_args.iter().decode() call in bindgen.

cc @fitzgen @BurntSushi

[emilio]

This is not funny at all, running that command basically OOMs my (fairly modern) machine while parsing arguments, something is not going well there.

[Yamakaky]

5min is not normal. On my bindgen repo, the parsing is also almost instant. I'll try later to remove code on the main to see what's wrong.

[BurntSushi]

Definitely a bug somewhere. I'll try to look at it today.

[emilio]

Thanks for looking into it @BurntSushi! :-)

[emilio]

Docopt was backed out in #37. Let us know if/when it's fixed, though :)

[Yamakaky]

Seems good docopt/docopt.rs#195