Xref the non-standard finite(3).

lib/libc/gen/isfinite.3

@@ -1,4 +1,4 @@
-.\"	$NetBSD: isfinite.3,v 1.3 2008/04/30 13:10:50 martin Exp $
+.\"	$NetBSD: isfinite.3,v 1.4 2011/08/06 11:02:41 jruoho Exp $
 .\"
 .\" Copyright (c) 2003 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 October 29, 2003
+.Dd August 6, 2011
 .Dt ISFINITE 3
 .Os
 .Sh NAME
@@ -66,6 +66,7 @@ Otherwise 0 is returned.
 .Sh ERRORS
 No errors are defined.
 .Sh SEE ALSO
+.Xr finite 3 ,
 .Xr fpclassify 3 ,
 .Xr isnormal 3 ,
 .Xr math 3 ,