[Bug libstdc++/67617] Non-standard const requirements imposed on associative container comparison objects

[daniel.kruegler at googlemail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=67617

--- Comment #6 from Daniel Krügler <daniel.kruegler at googlemail dot com> ---
(In reply to Daniel Krügler from comment #4)
> (In reply to Jonathan Wakely from comment #2)
> > Both Clang/libc++ and MSVC/Dinkumware reject it for the same reason.
> 
> I notice that the Dinkumware version associated with Visual Studio 2015
> accepts the code.

... assuming a proper definition of the operator() overload is provided,
of-course.