"Access to a protected member" build failure(s) — clang 2.9

This is a difference of interpretation between gcc and clang.
See gcc bug#52136 and clang bug #6840.
class address 
{
protected:
    static int parseNext(int a);
};


class mailbox : public address
{
    friend class mailboxField;
};

class mailboxField
{
    void parse(int a)
        {
            address::parseNext(a);
            // will work with:
            // mailbox::parseNext(a);
        }
};
clang will fail with:
$  clang++    -c mailboxField.cpp   
mailboxField.cpp:18:22: error: 'parseNext' is a protected member of 'address'
            address::parseNext(a);
                     ^
mailboxField.cpp:5:16: note: declared protected here
    static int parseNext(int a);
               ^
1 error generated.
PackageVersionSupposed error messageFull log Bug report
ardour 1:2.8.11-7libs/ardour/session.cc:2197:26: error: 'connecting_legal' is a protected member of 'ARDOUR::IO' n/a
fltk1.3 1.3.0-5Fl_x.cxx:1861:31: error: 'FORCE_POSITION' is a protected member of 'Fl_Widget' Log 755229
qmf 1.0.7~2011w23.2-2tst_qcop.cpp:234:35: error: 'Signals' is a protected member of 'QCopAdaptor' Log
qtractor 0.5.0-2qtractorClipFadeFunctor.cpp:178:40: error: 'FadeFunctor' is a protected member of 'qtractorClip' Log

4 errors