[PATCH] libstdc++: Fix ranges::join_view::_Iterator::operator-> [LWG 3500]

[Jonathan Wakely]

On 18/11/20 09:10 -0500, Patrick Palka via Libstdc++ wrote:
>This applies the proposed resolution of LWG 3500, which corrects the
>return type and constraints of this member function to use the right
>iterator type.  Additionally, a nearby local variable is uglified.
>
>Tested on x86_64-pc-linux-gnu, does this look OK for trunk and the 10
>branch?

OK, thanks.