Add HISTORY; from Jose Nazario

src/lib/libc/stdlib/strtonum.3

@@ -1,4 +1,4 @@
-.\" $OpenBSD: strtonum.3,v 1.6 2004/08/03 19:38:01 millert Exp $
+.\" $OpenBSD: strtonum.3,v 1.7 2004/09/21 15:01:59 millert Exp $
 .\"
 .\" Copyright (c) 2004 Ted Unangst
 .\"
@@ -135,3 +135,9 @@ The existing alternatives, such as
 and
 .Xr strtol 3
 are either impossible or difficult to use safely.
+.Sh HISTORY
+The
+.Fn strtonum
+function first appeared in
+.Ox
+3.6.