remove incorrect statement. the standard *does* require calloc to check

for overflow. stop talking about old broken systems, there's little use
for such info.

src/lib/libc/stdlib/malloc.3

@@ -30,9 +30,9 @@
 .\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 .\" SUCH DAMAGE.
 .\"
-.\"	$OpenBSD: malloc.3,v 1.89 2015/01/08 03:41:14 deraadt Exp $
+.\"	$OpenBSD: malloc.3,v 1.90 2015/03/14 08:07:17 tedu Exp $
 .\"
-.Dd $Mdocdate: January 8 2015 $
+.Dd $Mdocdate: March 14 2015 $
 .Dt MALLOC 3
 .Os
 .Sh NAME
@@ -437,11 +437,6 @@ other conforming implementations may return
 .Dv NULL
 in this case.
 .Pp
-The standard does not require
-.Fn calloc
-to check for integer overflow,
-but most modern implementations provide this check.
-.Pp
 The
 .Ev MALLOC_OPTIONS
 environment variable, the file