Fix a typo.

share/man/man9/roundup.9

@@ -1,4 +1,4 @@
-.\" $NetBSD: roundup.9,v 1.7 2011/04/08 08:49:19 wiz Exp $
+.\" $NetBSD: roundup.9,v 1.8 2011/06/01 11:19:19 jruoho Exp $
 .\"
 .\" Copyright (c) 2010 The NetBSD Foundation, Inc.
 .\" All rights reserved.
@@ -27,7 +27,7 @@
 .\" ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 .\" POSSIBILITY OF SUCH DAMAGE.
 .\"
-.Dd April 8, 2011
+.Dd June 1, 2011
 .Dt ROUNDUP 9
 .Os
 .Sh NAME
@@ -84,7 +84,7 @@ The behavior is undefined if
 is 0.
 .Sh EXAMPLES
 The following example rounds the variable
-.Va x
+.Va rx
 to a 32-bit boundary:
 .Bd -literal -offset indent
 uint16_t rx;