devel/clanlib: ignore libstdc++ 4.2 after r446644

In file included from Unix/clanapp.cpp:32:
In file included from ../../Sources/API/App/clanapp.h:35:
../../Sources/API/App/../Core/Text/string_types.h:64:9: error: explicit specialization of

non-template class 'hash'
          class hash<CL_String> : hash<const CL_String::char_type*>
                ^   ~~~~~~~~~~~

../../Sources/API/App/../Core/Text/string_types.h:64:27: error: unknown template name 'hash'

class hash<CL_String> : hash<const CL_String::char_type*>
                        ^

../../Sources/API/App/../Core/Text/string_types.h:69:16: error: expected '(' for function-style cast

or type construction
                          return hash<const CL_String::char_type*>::operator()(keyval.c_str());
                                 ~~~~^

../../Sources/API/App/../Core/Text/string_types.h:69:17: error: expected expression

return hash<const CL_String::char_type*>::operator()(keyval.c_str());
            ^

4 errors generated.

Pointy hat to: jbeich