Enabling C++ 11 on BB10 causes errors in qplatformdefs.h

When I first create the most basic QtQuick application with Qt Creator with the BB10 wizzard, it compiles and runs correctly on the simulator.
Then if I enable C++ 11 mode with:
QMAKE_CXXFLAGS = -Wc,-std=c+0x

Steps to reproduce:

1. Create QtQuick application in BB10
2. Compile
3. Enable QMAKE_CXXFLAGS = -Wc,-std=c+0x in .pro file
4. Clean the project
5. Rebuild all

Fails to compile with

In file included from c:/bbndk/target_10_0_9_1673/qnx6/usr/share/qt4/mkspecs/blackberry-x86-qcc/qplatformdefs.h:42:0,
from ../MyUhr/qmlapplicationviewer/qmlapplicationviewer.cpp:19:
c:/bbndk/target_10_0_9_1673/qnx6/usr/share/qt4/mkspecs/blackberry-x86-qcc/../qnx-x86-qcc/qplatformdefs.h: In function 'int getpagesize()':
c:/bbndk/target_10_0_9_1673/qnx6/usr/share/qt4/mkspecs/blackberry-x86-qcc/../qnx-x86-qcc/qplatformdefs.h:95:12: error: '::sysconf' has not been declared
c:/bbndk/target_10_0_9_1673/qnx6/usr/share/qt4/mkspecs/blackberry-x86-qcc/../qnx-x86-qcc/qplatformdefs.h:95:22: error: '_SC_PAGESIZE' was not declared in this scope
cc: C:/bbndk/host_10_0_9_404/win32/x86/usr/lib/gcc/i486-pc-nto-qnx8.0.0/4.6.3/cc1plus caught signal 1
make: *** [qmlapplicationviewer.o] Error 1