Edit the C++14 library warning header to not indicate experimental.

[Jonathan Wakely]

On 17/04/16 23:21 -0400, Ed Smith-Rowland wrote:
>
>Since the default is C++14 it seems apropos to *not* treat that C++ 
>version thusly in the warning in libstdc++.
>Ed
>
>OK for trunk?  And maybe some 6 branch later?

OK for trunk, for now. Thanks.

>2016-04-17  Edward Smith-Rowland  <3dw4rd@verizon.net>
>
>	* include/bits/c++14_warning.h: Do not refer C++14 as experimental.
>

>Index: include/bits/c++14_warning.h
>===================================================================
>--- include/bits/c++14_warning.h	(revision 235086)
>+++ include/bits/c++14_warning.h	(working copy)
>@@ -29,9 +29,9 @@
> #define _CXX14_WARNING_H 1
>
> #if __cplusplus <= 201103L
>-#error This file requires compiler and library support for the forthcoming \
>-ISO C++ 2014 standard. This support is currently experimental, and must be \
>-enabled with the -std=c++1y or -std=gnu++1y compiler options.
>+#error This file requires compiler and library support \
>+for the ISO C++ 2014 standard. This support must be enabled \
>+with the -std=c++14 or -std=gnu++14 compiler options.
> #endif
>
> #endif