Setup Qt for cross compile for raspberry pi

Question

I want to cross compile a project from my linux machine to a raspberry pi using Qt creator. Now I have set up a kit with compilers (that I tested to work) and a sysroot. However when I try to compile a simple "Hello world" example in Qt creator I get an error:

#include <iostream>

using namespace std;

int main()
{
    cout << "Hallo!!!" << endl;
    return 0;
}

/usr/include/c++/5/iostream:38: from /usr/include/c++/5/iostream:38, ~/sysroot/usr/include/features.h:364: error: sys/cdefs.h: No such file or directory

I see that Qt tries to use uses the following file for compilation:

/usr/include/c++/5/iostream

However it should use ~/sysroot/usr/include/c++/6/iostream

In the kit I use I have specified ~/sysroot as the sysroot, but it seems to use the other c++ includes. How can I change this?

EDIT : I have found a solution for the problem. See answers below. However I'm not sure if this is the best solution. I there are better ways, please let me know.

Answer 1

I found the problem. The default qmake build step adds the argument " -spec linux-g++" to the call to qmake. However this causes the wrong compiler to be chosen. Since I cannot remove the argument from the qmake build step, I removed the qmake step and added a custom build step which calls qmake and omits the -spec argument. This seems to work, but it feels a little dirty. Maybe there are better/cleaner solutions for this?