Include sys/types.h as well. Ray DeGennaro reports successful compiling on

AIX when this fix is applied and I cannot see how this will break any
systems.

include/curl/multi.h

@@ -51,6 +51,7 @@
 #else
 #include <sys/socket.h>
 #include <sys/time.h>
+#include <sys/types.h>
 #endif
 
 #include "curl.h"