Fix ctypes import

Fixes: #26

Signed-off-by: John Vandenberg <jayvdb@gmail.com>

Author: jayvdb

src/typecode/magic2.py

@@ -28,7 +28,7 @@
 # OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 # SOFTWARE.
 
-import ctypes
+import ctypes.util
 import glob
 import os
 import sys