Update COPYING for SHA1 code

COPYING

@@ -2597,3 +2597,11 @@ FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT.  IN NO EVENT SHALL
 THE AUTHORS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
 IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
 CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+
+
+
+The following statement applies only to the SHA1 code in render/:
+'SHA-1 in C
+By Steve Reid <steve@edmweb.com>
+100% Public Domain'
+