Compiler options including spaces break clang code model on CMake projects

When using compiler options with a space between the option and its argument, clang code model breaks (see screenshots about code model details).

Code highlighting also stops working, and code navigation with Ctrl+Click is partially broken on bigger projects.

The root problem seems to be the fact that toolkit defines are somehow lost when using compiler options with spaces, and Qt Creator doesn't infer the right C++ version for the project anymore.