Change recvfrom's sixth argument data type to the 'historically standard' 'int'

data type for systems where this sixth argument is prototyped as a void pointer.

Start of thread: http://curl.haxx.se/mail/lib-2008-07/0153.html

setup_once.h

@@ -223,7 +223,7 @@ struct timeval {
 
 
 #ifdef RECVFROM_TYPE_ARG6_IS_VOID
-#  define RECVFROM_ARG6_T unsigned int
+#  define RECVFROM_ARG6_T int
 #else
 #  define RECVFROM_ARG6_T RECVFROM_TYPE_ARG6
 #endif