(PECL runkit >= 0.7.0)
runkit_constant_add — Similar to define(), but allows defining in class definitions as well
Name of constant to declare. Either a string to indicate a global constant, or classname::constname to indicate a class constant.
NULL, Bool, Long, Double, String, or Resource value to store in the new constant.
如果成功则返回 TRUE，失败则返回 FALSE。