IB: 0.2 part IV

* BEGIN_TS(), COMMIT_TS() SQL functions;
* VTQ instead of packed stores secs + usecs like my_timestamp_to_binary() does;
* versioned SELECT to IB is translated with COMMIT_TS();
* SQL fixes:
  - FOR_SYSTEM_TIME_UNSPECIFIED condition compares to TIMESTAMP_MAX_VALUE;
  - segfault fix #36: multiple execute of prepared stmt;
  - different tables to same stored procedure fix (#39)
* Fixes of previous parts: ON DUPLICATE KEY, other misc fixes.

sql/sql_class.h

@@ -940,6 +940,11 @@ public:
 
   enum_state state;
 
+protected:
+  friend class sp_head;
+  bool is_stored_procedure;
+
+public:
   /* We build without RTTI, so dynamic_cast can't be used. */
   enum Type
   {
@@ -947,7 +952,8 @@ public:
   };
 
   Query_arena(MEM_ROOT *mem_root_arg, enum enum_state state_arg) :
-    free_list(0), mem_root(mem_root_arg), state(state_arg)
+    free_list(0), mem_root(mem_root_arg), state(state_arg),
+    is_stored_procedure(state_arg == STMT_INITIALIZED_FOR_SP ? true : false)
   { INIT_ARENA_DBUG_INFO; }
   /*
     This constructor is used only when Query_arena is created as
@@ -967,6 +973,8 @@ public:
   { return state == STMT_PREPARED || state == STMT_EXECUTED; }
   inline bool is_conventional() const
   { return state == STMT_CONVENTIONAL_EXECUTION; }
+  inline bool is_sp_execute() const
+  { return is_stored_procedure; }
 
   inline void* alloc(size_t size) { return alloc_root(mem_root,size); }
   inline void* calloc(size_t size)
@@ -6021,5 +6029,4 @@ public:
 
 
 #endif /* MYSQL_SERVER */
-
 #endif /* SQL_CLASS_INCLUDED */