Fix typo in manual page reference.

Index: src/lib/libc/stdlib/a64l.3
===================================================================
RCS file: /home/ncvs/src/lib/libc/stdlib/a64l.3,v
retrieving revision 1.1
diff -u -r1.1 a64l.3
--- src/lib/libc/stdlib/a64l.3	24 Dec 2005 22:37:59 -0000	1.1
+++ src/lib/libc/stdlib/a64l.3	26 Feb 2006 15:28:20 -0000
@@ -159,7 +159,7 @@
 .Fn l64a
 returns a pointer to an empty string.
 .Sh SEE ALSO
-.Xr stroul 3
+.Xr strtoul 3
 .Sh HISTORY
 The
 .Fn a64l ,