Made -outdev stdio:/dev/fd/1 safe for single session runs

test/xorriso_private.h

@@ -96,6 +96,9 @@ struct XorrisO { /* the global context of xorriso */
 
  char outdev[SfileadrL];
  void *out_drive_handle; /* interpreted only by xorrisoburn.c */
+ int dev_fd_1; /* The fd which substitutes for /dev/fd/1 and is
+                     connected to externaly perveived stdout.
+                  */
 
  int ban_stdio_write;
  int do_dummy;