Bump standards years, as we conform to the new versions too

ok jmc@

src/lib/libc/string/strerror.3

@@ -29,9 +29,9 @@
 .\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 .\" SUCH DAMAGE.
 .\"
-.\"	$OpenBSD: strerror.3,v 1.10 2011/07/25 00:38:53 schwarze Exp $
+.\"	$OpenBSD: strerror.3,v 1.11 2012/03/26 05:07:38 guenther Exp $
 .\"
-.Dd $Mdocdate: July 25 2011 $
+.Dd $Mdocdate: March 26 2012 $
 .Dt STRERROR 3
 .Os
 .Sh NAME
@@ -106,11 +106,11 @@ The message will be truncated to fit.
 The
 .Fn strerror
 function conforms to
-.St -ansiC .
+.St -ansiC-99 .
 The
 .Fn strerror_r
 function conforms to
-.St -p1003.1 .
+.St -p1003.1-2008 .
 .Sh HISTORY
 The
 .Fn strerror