[Bug libstdc++/63920] Any regular expression should not match an empty sequence if match_not_null is specified

[kariya_mitsuru at hotmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=63920

--- Comment #1 from Mitsuru Kariya <kariya_mitsuru at hotmail dot com> ---
Sorry, the last link was mistaken.
The right link is below.
http://melpon.org/wandbox/permlink/v1HhsIs8d2LrmUk9