(PECL runkit7 >= Unknown)
runkit7_constant_redefine — Redefine an already defined constant
constant_name
       Constant to redefine.  Either the name of a global constant,
       or classname::constname indicating class constant.
     
valueValue to assign to the constant.
new_visibility
      The new visibility of the constant, for class constants.
      Unchanged by default.
      One of the RUNKIT7_ACC_* constants.
     
   成功时返回 true, 或者在失败时返回 false。