[patch] For BZ #17328, mark __errno_location with __attribute__((returns_nonnull)) for gcc >=4.9.0

[Joseph Myers]

On Mon, 2 Mar 2015, Roland McGrath wrote:

> Then a savvy user could '#undef errno' to use the TLS version.  We could

I don't think we should encourage users to #undef errno (something 
undefined in ISO C, and that wouldn't work with current glibc).

-- 
Joseph S. Myers
joseph@codesourcery.com