Clean compile on Mac OS X

Changes by Neil Pennell
https://github.com/OpenNebula/one/pull/2
(cherry picked from commit 2803d7e964)

src/mad/utils/tty_expect.c

@@ -14,7 +14,11 @@
 /* limitations under the License.                                             */
 /* -------------------------------------------------------------------------- */
 
+#ifdef __APPLE__
+#include <util.h>
+#else
 #include <pty.h>
+#endif
 
 #include <stdio.h>
 #include <stdlib.h>