WL#5030: Split and remove mysql_priv.h

This patch:

- Moves all definitions from the mysql_priv.h file into
  header files for the component where the variable is
  defined
- Creates header files if the component lacks one
- Eliminates all include directives from mysql_priv.h
- Eliminates all circular include cycles
- Rename time.cc to sql_time.cc
- Rename mysql_priv.h to sql_priv.h

sql/event_parse_data.h

@@ -16,6 +16,12 @@
 #ifndef _EVENT_PARSE_DATA_H_
 #define _EVENT_PARSE_DATA_H_
 
+#include "sql_list.h"                           /* Sql_alloc */
+
+class Item;
+class THD;
+class sp_name;
+
 #define EVEX_GET_FIELD_FAILED   -2
 #define EVEX_BAD_PARAMS         -5
 #define EVEX_MICROSECOND_UNSUP  -6