[Bug libstdc++/51932] Cannot use std::errno with

[redi at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=51932

--- Comment #1 from Jonathan Wakely <redi at gcc dot gnu.org> 2012-01-21 
14:06:51 UTC ---
errno is required to be a macro, you can't use std::NULL either