[Bug c++/85251] Using declaration for base class constructor looses explicit.

[pinskia at gcc dot gnu.org via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=85251

--- Comment #1 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
GCC, ICC, and MSVC all do the same thing and calls A(int).