Fix shared memory connection handling on Windows. (Bug #12723)

vio/viosocket.c:
  Don't pay attention to changes of nonblocking flag for shared memory
  connections.

vio/viosocket.c

@@ -99,7 +99,7 @@ int vio_blocking(Vio * vio __attribute__((unused)), my_bool set_blocking_mode,
 #endif /* !defined(NO_FCNTL_NONBLOCK) */
 #else /* !defined(__WIN__) && !defined(__EMX__) */
 #ifndef __EMX__
-  if (vio->type != VIO_TYPE_NAMEDPIPE)  
+  if (vio->type != VIO_TYPE_NAMEDPIPE && vio->type != VIO_TYPE_SHARED_MEMORY)
 #endif
   { 
     ulong arg;