Address gcc warning:

conn_telnet.c: In function 'telnet_output_thread':
conn_telnet.c:95:56: warning: passing argument 6 of 'telnet_expand' from incompatible pointer type
../sbbs3/telnet.h:168:18: note: expected 'unsigned char **' but argument is of type 'char **'

src/syncterm/conn_telnet.c

@@ -92,7 +92,7 @@ void telnet_output_thread(void *args)
 			wr=conn_buf_get(&conn_outbuf, conn_api.wr_buf, conn_api.wr_buf_size);
 			pthread_mutex_unlock(&(conn_outbuf.mutex));
 			wr = telnet_expand(conn_api.wr_buf, wr, (BYTE *)ebuf, sizeof(ebuf)
-				,telnet_local_option[TELNET_BINARY_TX]!=TELNET_DO, &buf);
+				,telnet_local_option[TELNET_BINARY_TX]!=TELNET_DO, (uchar**)&buf);
 			sent=0;
 			while(sent < wr) {
 				FD_ZERO(&wds);