It is safe to pass free() a NULL pointer since C89; update example to

this effect.  OK deraadt@ pvalchev@

src/lib/libc/stdlib/malloc.3

@@ -30,7 +30,7 @@
 .\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 .\" SUCH DAMAGE.
 .\"
-.\"	$OpenBSD: malloc.3,v 1.30 2003/09/25 11:10:56 deraadt Exp $
+.\"	$OpenBSD: malloc.3,v 1.31 2003/09/26 05:57:02 millert Exp $
 .\"
 .Dd August 27, 1996
 .Dt MALLOC 3
@@ -159,8 +159,7 @@ Better code looks like this:
 .Bd -literal -offset indent
 newsize = size + 50;
 if ((newp = realloc(p, newsize)) == NULL) {
-	if (p)
-		free(p);
+	free(p);
 	p = NULL;
 	size = 0;
 	return (NULL);