[Patch] Change default executor to DFS in regex

[Paolo Carlini]

On 10/19/2013 11:28 PM, Tim Shen wrote:
> I see. Here's the macro version. Thanks! 
Mostly Ok, but the macro is completely undocumented. Please change the 
comment which says: "... more than certain number of quantifiers..." to 
actually mention the macro, thus, say: "... more than 
_GLIBCXX_REGEX_DFS_QUANTIFIERS_LIMIT quantifiers...". I would also add, 
before the #ifndef, a comment, say "// See below about its meaning. The 
default value of 1 appears to be a good compromise.

Ok with those changes.

Thanks,
Paolo.