[Bug libstdc++/61347] std::distance(list.first(),list.end()) in O(1)

[redi at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=61347
Bug 61347 depends on bug 49561, which changed state.

Bug 49561 Summary: [C++0x] std::list::size complexity
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=49561

           What    |Removed                     |Added
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             Status|REOPENED                    |RESOLVED
         Resolution|---                         |FIXED