[v3 PATCH] Implement LWG 2806, Base class of bad_optional_access.

[Jonathan Wakely]

On 12/03/17 13:47 +0200, Ville Voutilainen wrote:
>Tested on Linux-x64.
>
>2017-03-12  Ville Voutilainen  <ville.voutilainen@gmail.com>
>
>    Implement LWG 2806, Base class of bad_optional_access.
>    * include/std/optional (bad_optional_access):
>    Derive from std::exception.
>    (bad_optional_access::bad_optional_access): Adjust.
>    (bad_optional_access::what): New.
>    (__throw_bad_optional_access(const char*)):
>    Remove the parameter and adjust calls.
>    * testsuite/20_util/optional/cons/value_neg.cc: Adjust.
>    * testsuite/20_util/optional/typedefs.cc: Likewise.

OK, thanks.