Fixups for EDG front end.
* include/ext/rope: Instead of non-existent function
_Data_allocate, use allocator's allocate. Use this.
(namespace _Rope_constants): Move _S_max_rope_depth, and _Tag
enumerations from _Rope_RopeRep here.
* include/ext/ropeimpl.h: Same.
* src/ext-inst.cc (_S_min_len): Fix up definition.
* config/locale/gnu/ctype_members.cc: Qualify base class members
with this.
* config/locale/generic/ctype_members.cc: Same.
* config/locale/gnu/messages_members.h: Same.
* config/locale/generic/messages_members.h: Same.
* src/ctype.cc: Same.
* include/bits/codecvt.h: Same.