Include a link back to the original project

Author: bjori

src/mongoc/mongoc-sspi.c

@@ -12,6 +12,8 @@
  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  * See the License for the specific language governing permissions and
  * limitations under the License.
+ *
+ * This file originates from https://github.com/mongodb-labs/winkerberos
  */
 
 #include "mongoc-config.h"