[Bug libstdc++/83598] std::basic_regex C++14 conformance issue: resulting flags != passed flags

[redi at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=83598

Jonathan Wakely <redi at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |NEW
   Last reconfirmed|                            |2017-12-27
     Ever confirmed|0                           |1

--- Comment #1 from Jonathan Wakely <redi at gcc dot gnu.org> ---
I think we need to store exactly the flags passed to the constructor, and then
apply the (__f | ECMAScript) operation when we test it, not in the constructor.