Do not describe -std=c11 etc. as experimental in c.opt help text

[Joseph Myers]

I noticed that c.opt still described -std=c11 and related options as
experimental in the --help text.  This patch fixes this.

Jason, note that -std=gnu++11 and -std=gnu++14 still have that text,
contrary to the descriptions of -std=c++11 and -std=c++14.

Bootstrapped with no regressions on x86_64-pc-linux-gnu.  Applied to
mainline.

2015-10-01  Joseph Myers  <joseph@codesourcery.com>

	* c.opt (std=c11): Do not describe as experimental.
	(std=gnu11): Likewise.
	(std=iso9899:2011): Likewise.

Index: gcc/c-family/c.opt
===================================================================
--- gcc/c-family/c.opt	(revision 228327)
+++ gcc/c-family/c.opt	(working copy)
@@ -1656,7 +1656,7 @@
 
 std=c11
 C ObjC
-Conform to the ISO 2011 C standard (experimental and incomplete support)
+Conform to the ISO 2011 C standard
 
 std=c1x
 C ObjC Alias(std=c11)
@@ -1713,7 +1713,7 @@
 
 std=gnu11
 C ObjC
-Conform to the ISO 2011 C standard with GNU extensions (experimental and incomplete support)
+Conform to the ISO 2011 C standard with GNU extensions
 
 std=gnu1x
 C ObjC Alias(std=gnu11)
@@ -1753,7 +1753,7 @@
 
 std=iso9899:2011
 C ObjC Alias(std=c11)
-Conform to the ISO 2011 C standard (experimental and incomplete support)
+Conform to the ISO 2011 C standard
 
 traditional
 Driver

-- 
Joseph S. Myers
joseph@codesourcery.com