Fixed lp:814238 "safe_mutex issues must be assertions in debug binary"

Added --debug-assert-on-error variable which, if set, will cause safe_mutex to assert if it founds an error.

include/my_sys.h:
  Added my_assert_on_error
mysys/my_static.c:
  Added my_assert_on_error
mysys/thr_mutex.c:
  Assert when found wrong mutex usage if my_assert_on_error is set
sql/mysqld.cc:
  Added setting of my_assert_on_error

include/my_sys.h

@@ -255,6 +255,7 @@ extern ulong    my_file_total_opened;
 extern ulong    my_sync_count;
 extern uint	mysys_usage_id;
 extern my_bool	my_init_done;
+extern my_bool  my_assert_on_error;
 extern myf      my_global_flags;        /* Set to MY_WME for more error messages */
 					/* Point to current my_message() */
 extern void (*my_sigtstp_cleanup)(void),

mysys/my_static.c

@@ -32,7 +32,8 @@ char		NEAR curr_dir[FN_REFLEN]= {0},
 ulong		my_stream_opened=0,my_file_opened=0, my_tmp_file_created=0;
 ulong           my_file_total_opened= 0;
 int		NEAR my_umask=0664, NEAR my_umask_dir=0777;
-myf             my_global_flags;
+myf             my_global_flags= 0;
+my_bool         my_assert_on_error= 0;
 #ifndef THREAD
 int		NEAR my_errno=0;
 #endif

mysys/thr_mutex.c

@@ -836,6 +836,7 @@ static void print_deadlock_warning(safe_mutex_t *new_mutex,
                         mutex_root->file, mutex_root->line));
   }
   fflush(stderr);
+  DBUG_ASSERT(my_assert_on_error == 0);
   DBUG_VOID_RETURN;
 }
 

sql/mysqld.cc

@@ -6068,7 +6068,9 @@ enum options_mysqld
   OPT_SECURE_FILE_PRIV,
   OPT_MIN_EXAMINED_ROW_LIMIT,
   OPT_LOG_SLOW_SLAVE_STATEMENTS,
-  OPT_DEBUG_CRC, OPT_DEBUG_ON, OPT_DEBUG_ASSERT_IF_CRASHED_TABLE, OPT_OLD_MODE,
+  OPT_DEBUG_CRC, OPT_DEBUG_ON, OPT_DEBUG_ASSERT_IF_CRASHED_TABLE,
+  OPT_DEBUG_ASSERT_ON_ERROR,
+  OPT_OLD_MODE,
   OPT_TEST_IGNORE_WRONG_OPTIONS, OPT_TEST_RESTART,
 #if defined(ENABLED_DEBUG_SYNC)
   OPT_DEBUG_SYNC_TIMEOUT,
@@ -6243,6 +6245,10 @@ struct my_option my_long_options[] =
    "Do an assert in handler::print_error() if we get a crashed table",
    &debug_assert_if_crashed_table, &debug_assert_if_crashed_table,
    0, GET_BOOL, NO_ARG, 0, 0, 0, 0, 0, 0},
+  {"debug-assert-on-error", OPT_DEBUG_ASSERT_ON_ERROR,
+   "Do an assert in various functions if we get a fatal error",
+   &my_assert_on_error, &my_assert_on_error,
+   0, GET_BOOL, NO_ARG, 0, 0, 0, 0, 0, 0},
 #endif
   {"default-character-set", OPT_DEFAULT_CHARACTER_SET_OLD, 
    "Set the default character set (deprecated option, use --character-set-server instead).",
@@ -9422,14 +9428,17 @@ static int get_options(int *argc,char **argv)
   my_crc_dbug_check= opt_my_crc_dbug_check;
 
   /*
-    Log mysys errors when we don't have a thd or thd->log_all_errors is set (recovery) to
-    the log.  This is mainly useful for debugging strange system errors.
+    Log mysys errors when we don't have a thd or thd->log_all_errors is set
+    (recovery) to the log.  This is mainly useful for debugging strange system
+    errors.
   */
   if (global_system_variables.log_warnings >= 10)
     my_global_flags= MY_WME | ME_JUST_INFO;
   /* Log all errors not handled by thd->handle_error() to my_message_sql() */
   if (global_system_variables.log_warnings >= 11)
     my_global_flags|= ME_NOREFRESH;
+  if (my_assert_on_error)
+    debug_assert_if_crashed_table= 1;
 
   /* long_query_time is in microseconds */
   global_system_variables.long_query_time= max_system_variables.long_query_time=