[Patch] Fix warnings in regex

[Marc Glisse]

On Thu, 17 Oct 2013, 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?

-Wsystem-headers ?

(note also the -P flag)

-- 
Marc Glisse