Bug#799556: Unwanted assert causing failure

[Jeffrey Walton]

There's an unwanted assert causing the failure in
gdb/linux-thread-db.c. Around line 1675, guard the assert based on
__ILP32__:

#if !defined(__ILP32__) && !defined(_ILP32)
  /* See comment in thread_db_update_thread_list.  */
  gdb_assert (!target_has_execution || thread_db_use_events ());
#endif

Once the assert is removed for the X32 platform, the program can be
executed under GDB.