[Patch] Fix warnings in regex

[Paolo Carlini]

On 10/17/2013 08:50 PM, Tim Shen wrote:
> ...to prevent potential bugs.
>
> By the way, I execute `g++ -E file.cc > prep.cc && sed -i 's|^#.*$||'
> prep.cc && g++ -Wall prep.cc 2> log` to get all warnings. Do we have a
> better way?
>
> Bootstraps and tested under -m64 and -m32.
Please explain in the ChangeLog *which* warnings.

Ok with that change.

Thanks,
Paolo.