[Development] -Winconsistent-missing-override warning with latest Xcode and Qt 5.5

[Stephen Kelly]

Hello,

I just tried building Qt 5.5 with Xcode 6.3.2. It built, but emitted
many warnings for each translation unit about
-Winconsistent-missing-override.

In file included from
/Users/ske/dev/src/qt55/qtdeclarative/src/qml/debugger/qqmldebugserver.cpp:34:
In file included from
/Users/ske/dev/src/qt55/qtdeclarative/src/qml/debugger/qqmldebugserver_p.h:39:
In file included from
../../include/QtQml/5.5.0/QtQml/private/qqmldebugservice_p.h:1:
../../include/QtQml/5.5.0/QtQml/private/../../../../../../src/qml/debugger/qqmldebugservice_p.h:60:5:
warning: unknown warning group '-Winconsistent-missing-override',
ignored [-Wunknown-pragmas]
    Q_OBJECT
    ^

/Users/ske/dev/prefix55/lib/QtCore.framework/Headers/qobjectdefs.h:156:5:
note: expanded from macro 'Q_OBJECT'
    Q_OBJECT_NO_OVERRIDE_WARNING \
    ^

/Users/ske/dev/prefix55/lib/QtCore.framework/Headers/qobjectdefs.h:146:45:
note: expanded from macro 'Q_OBJECT_NO_OVERRIDE_WARNING'
£  define Q_OBJECT_NO_OVERRIDE_WARNING
QT_WARNING_DISABLE_CLANG("-Winconsistent-missing-override")
                                            ^

/Users/ske/dev/prefix55/lib/QtCore.framework/Headers/qcompilerdetection.h:1125:49:
note: expanded from macro 'QT_WARNING_DISABLE_CLANG'
£  define QT_WARNING_DISABLE_CLANG(text)        QT_DO_PRAGMA(clang
diagnostic ignored text)
                                                ^

/Users/ske/dev/prefix55/lib/QtCore.framework/Headers/qcompilerdetection.h:1096:49:
note: expanded from macro 'QT_DO_PRAGMA'
£define QT_DO_PRAGMA(text)                      _Pragma(£text)
                                                ^

<scratch space>:23:27: note: expanded from here
 clang diagnostic ignored "-Winconsistent-missing-override"
                          ^

I see qtbase commit v5.5.0-alpha1~786 (Fix Clang warning about
inconsistent use of C++11 override, 2014-12-18). It attempts to affect
'Q_CC_CLANG >= 306'. Do the Qt macros know the difference between
'clang' and 'apple clang'? All version checks of 'clang'-based
compilers must be aware of the difference and check both compilers.

Thanks,

Steve.