[Bug libstdc++/60970] New: Support std::hash with enum types (LWG 2148)

[gromer at google dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=60970

            Bug ID: 60970
           Summary: Support std::hash with enum types (LWG 2148)
           Product: gcc
           Version: unknown
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: libstdc++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: gromer at google dot com

std::hash<T> appears to be undefined when T is an enum type, contrary to the
resolution of LWG 2148
(http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#2148).