Consider upstreaming crossword library fix

[davide125]

This package vendors a copy of the crossword library with one fix on top (dc5a6cf). Please consider submitting this fix to the upstream project.

[saulpw]

I don't have time for this project at the moment, so if you feel motivated to submit the change upstream, please do! The change is so small that I can't claim ownership of it.

[davide125]

Put up svisser/crossword#5 for this.