Telnet: fix win32 work.

Code by fpostma on the forum - fpostma __ xs4all | nl
Thanks to Lorni for testing.
Close #2022

modules/control/telnet.c

@@ -30,6 +30,10 @@
 # include "config.h"
 #endif
 
+#ifdef WIN32
+# include "winsock2.h"
+#endif
+
 #include <vlc_common.h>
 #include <vlc_plugin.h>
 #include <vlc_interface.h>
@@ -371,6 +375,13 @@ static void Run( intf_thread_t *p_intf )
                                    cl->i_mode + 2 );
                 }
 
+#ifdef WIN32
+                if( i_recv <= 0 && WSAGetLastError() == WSAEWOULDBLOCK )
+                {
+                    errno=EAGAIN;
+                }
+#endif
+
                 if (i_recv <= 0 && ( end || errno != EAGAIN ) )
                     goto drop;
             }