re PR c++/27667 (ICE with in-class specialization)

re PR c++/27667 (ICE with in-class specialization)

        PR c++/27667
        * cp-tree.h (begin_specialization): Return bool instead of void.
        * pt.c (check_specialization_scope): Likwise. Adjust comment.
        Return false if a specialization isn't permitted in the current scope,.
        (begin_specialization): Use the return value of
        check_specialization_scope.
        * parser.c (cp_parser_explicit_specialization): If
        begin_specialization returned false, skip the rest of the
        specialization.

        * g++.dg/template/spec33.C: New test.
        * g++.old-deja/g++.pt/spec20.C: Adjust error markers.

From-SVN: r117206