新的全局常量

## New Global Constants ### [Core Predefined Constants](http://php.net/manual/en/reserved.constants.php) * `PHP_INT_MIN` ### [LibXML](http://php.net/manual/en/book.libxml.php) * `LIBXML_BIGLINES` ### [PCRE](http://php.net/manual/en/book.pcre.php) * `PREG_JIT_STACKLIMIT_ERROR` ### [POSIX](http://php.net/manual/en/book.posix.php) * `POSIX_RLIMIT_AS` * `POSIX_RLIMIT_CORE` * `POSIX_RLIMIT_CPU` * `POSIX_RLIMIT_DATA` * `POSIX_RLIMIT_FSIZE` * `POSIX_RLIMIT_LOCKS` * `POSIX_RLIMIT_MEMLOCK` * `POSIX_RLIMIT_MSGQUEUE` * `POSIX_RLIMIT_NICE` * `POSIX_RLIMIT_NOFILE` * `POSIX_RLIMIT_NPROC` * `POSIX_RLIMIT_RSS` * `POSIX_RLIMIT_RTPRIO` * `POSIX_RLIMIT_RTTIME` * `POSIX_RLIMIT_SIGPENDING` * `POSIX_RLIMIT_STACK` * `POSIX_RLIMIT_INFINITY` ### [Zlib](http://php.net/manual/en/book.zlib.php) * `ZLIB_BLOCK` * `ZLIB_FINISH` * `ZLIB_FULL_FLUSH` * `ZLIB_NO_FLUSH` * `ZLIB_PARTIAL_FLUSH` * `ZLIB_SYNC_FLUSH`