Qt Creator Clang Code Model 4.8.1 not working for cross-compile with cmake toolchain file

[Hugo van den Brand]

I use a basic QtQuick application with CMakeLists.txt generated by qtcreator.
I configured a basic desktop kit (specifying C/CXX compiler, Qt version, standard cmake settings).
This desktop kit works fine for building and the Code Model works as expected.

I also a crosscompiling kit using a Yocto SDK in which I only set the sysroot (/opt/poky/2.2.0/sysroots/cortexa9hf-neon-poky-linux-gnueabi), debugger and cmake.
As cmake arguments I have:

CMAKE_TOOLCHAIN_FILE:INTERNAL=/opt/poky/2.2.0/sysroots/x86_64-pokysdk-linux/usr/share/cmake/OEToolchainConfig.cmake

Qtcreator is able to compile with this kit, but the Clang Code model fails to find type_traits.

By using export QT_LOGGING_RULES=qtc.clang*=true from Qt Creator Clang Code Model, I see that the include path is limited to just:

#include "..." search starts here:
#include <...> search starts here:
 /home/appdev/builds/build-colibtest-Embedded_ARM_GNUEABI-Default
 /home/appdev/colibtest
 /home/appdev/builds/build-colibtest-Embedded_ARM_GNUEABI-Default/colibtest_autogen/include
 /opt/poky/2.2.0/sysroots/cortexa9hf-neon-poky-linux-gnueabi/usr/include/qt5
 /opt/poky/2.2.0/sysroots/cortexa9hf-neon-poky-linux-gnueabi/usr/include/qt5/QtCore
 /opt/poky/2.2.0/sysroots/cortexa9hf-neon-poky-linux-gnueabi/usr/lib/qt5/mkspecs/linux-oe-g++
 /opt/poky/2.2.0/sysroots/cortexa9hf-neon-poky-linux-gnueabi/usr/include/qt5/QtQuick
 /opt/poky/2.2.0/sysroots/cortexa9hf-neon-poky-linux-gnueabi/usr/include/qt5/QtQml
 /opt/poky/2.2.0/sysroots/cortexa9hf-neon-poky-linux-gnueabi/usr/include/qt5/QtNetwork
 /opt/poky/2.2.0/sysroots/cortexa9hf-neon-poky-linux-gnueabi/usr/include/qt5/QtGui
 /tmp/QtCreator-DoOePy/clang-uiheader-yzrCSu
 /opt/qtcreator/libexec/qtcreator/clang/lib/clang/7.0.0/include
End of search list.

I found a similar topic on code model failure in cross compiling in which the issue is resolved by setting CMAKE_SYSROOT.

I tried this both in the Project Build settings and by adding it to the toolchain file with either
set( CMAKE_SYSROOT $ENV{OECORE_TARGET_SYSROOT} ) or
set( CMAKE_SYSROOT /opt/poky/2.2.0/sysroots/cortexa9hf-neon-poky-linux-gnueabi )

If I add it in the toolchain file I do not see CMAKE_SYSROOT in the project build settings.
In both cases I don't see any difference in the code model behavior.

Could this be a known issue that is resolved in a newer release or does anybody have a clue how to solve this?