Build error on 5.6.0 branch for -no-opengl: only virtual member functions can be marked 'override'

When buildiung on Mac OSX 10.11 with Xcode 7.3 the following error occurs:

05:30:33][Step 2/2] /Applications/Xcode.app/Contents/Developer/usr/bin/make -f Makefile.Debug install
[05:30:33][Step 2/2] Makefile.Debug:3139: warning: overriding commands for target `.moc/debug/main.moc'
[05:30:33][Step 2/2] Makefile.Debug:2411: warning: ignoring old commands for target `.moc/debug/main.moc'
[05:30:34][Step 2/2] /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/clang++ -c -pipe -stdlib=libc++ -g -fPIC -std=c++11 -isysroot /Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX10.11.sdk -mmacosx-version-min=10.7 -fvisibility=hidden -fvisibility-inlines-hidden -fno-exceptions -Wall -W -fPIC -DQT_NO_MTDEV -DQT_NO_LIBUDEV -DQT_NO_EVDEV -DQT_NO_TSLIB -DQT_NO_LIBINPUT -DQT_NO_EXCEPTIONS -D_LARGEFILE64_SOURCE -D_LARGEFILE_SOURCE -DQT_STATICPLUGIN -DQT_PLUGIN -DQT_PLATFORMSUPPORT_LIB -DQT_PRINTSUPPORT_LIB -DQT_WIDGETS_LIB -DQT_GUI_LIB -DQT_CORE_LIB -I. -I../../../../include -I../../../../include/QtPlatformSupport -I../../../../include/QtPlatformSupport/5.6.0 -I../../../../include/QtPlatformSupport/5.6.0/QtPlatformSupport -I../../../../include/QtPrintSupport/5.6.0 -I../../../../include/QtPrintSupport/5.6.0/QtPrintSupport -I../../../../include/QtWidgets/5.6.0 -I../../../../include/QtWidgets/5.6.0/QtWidgets -I../../../../include/QtGui/5.6.0 -I../../../../include/QtGui/5.6.0/QtGui -I../../../../include/QtPrintSupport -I../../../../include/QtWidgets -I../../../../include/QtGui -I../../../../include/QtCore/5.6.0 -I../../../../include/QtCore/5.6.0/QtCore -I../../../../include/QtCore -I.moc/debug -I../../../../mkspecs/macx-clang -o .obj/debug/qcocoaintegration.o qcocoaintegration.mm
[05:30:53][Step 2/2] In file included from qcocoaintegration.mm:37:
[05:30:53][Step 2/2] ./qcocoabackingstore.h:54:28: error: only virtual member functions can be marked 'override'
[05:30:53][Step 2/2] QImage toImage() const Q_DECL_OVERRIDE;
[05:30:53][Step 2/2] ^~~~~~~~~~~~~~~
[05:30:53][Step 2/2] ../../../../include/QtCore/../../src/corelib/global/qcompilerdetection.h:1023:26: note: expanded from macro 'Q_DECL_OVERRIDE'
[05:30:53][Step 2/2] # define Q_DECL_OVERRIDE override
[05:30:53][Step 2/2] ^
[05:30:54][Step 2/2] 1 error generated.
[05:30:54][Step 2/2] make[6]: *** [.obj/debug/qcocoaintegration.o] Error 1
[05:30:54][Step 2/2] make[5]: *** [debug-install] Error 2
[05:30:54][Step 2/2] make[4]: *** [sub-cocoa-install_subtargets] Error 2
[05:30:54][Step 2/2] make[3]: *** [sub-platforms-install_subtargets] Error 2
[05:30:54][Step 2/2] make[2]: *** [sub-plugins-install_subtargets] Error 2
[05:30:54][Step 2/2] make[1]: *** [sub-src-install_subtargets] Error 2
[05:30:54][Step 2/2] make: ***odule-qtbase-install_subtargets] Error 2
[05:30:54][Step 2/2] Process exited with code 2

Full build log attached. The following steps are done to build the code:

perl init-repository --berlin

ROOT='%system.teamcity.build.checkoutDir%'
export PATH="$ROOT/qtbase/bin:$PATH"

./configure -prefix "$ROOT/output" -continue -debug-and-release -opensource -confirm-license -nomake tools -nomake examples -nomake tests -skip qtxmlpatterns -skip qtmultimedia -skip qtwebkit -skip qtwebkit-examples -c++11 -static -qt-sql-sqlite -no-icu -openssl-linked -strip -no-dbus -no-audio-backend -no-qml-debug -no-opengl -largefile

make