Profiles for MinGW lack "qbs.architecture"

I tried to use qbs.architecture to decide between x86 or x86_64 binaries to link with. This works fine with the msvc kit, but not with the MinGW kit. Here is some test code to just output the content of the variables:

import qbs

Project {
    id: project
    name: {
        console.info("Start of output")
        console.info(qbs.toolchain)
        console.info(qbs.architecture)
        console.info("End of output")
        return "MyProject"
    }
}

When I compile this with "Qt 5.12.3 64bit (MSVC 2017)" it outputs:

Start of output
msvc
x86_64
End of output

When I compile this with "Qt 5.11.2 MinGW 32bit" it outputs:

Start of output
mingw,gcc
undefined
End of output

Notice that qbs.architecture is "undefined" now. I found the place where the kits are stored from Qt Creator:

C:\Users\<user>\AppData\Roaming\QtProject\qtcreator\qbs\1.13.1\qbs.conf

and this file shows that the MinGW kits just lack this value.

I also looked at our build server, Qbs 1.14.0, and qbs config --list show the same thing with no qbs.architecture for our MinGW profiles.

We can of course just add this architecture manually, but it would be nice to be able to write something in the Qbs file that just works on clean installs. I tried to read "cpp.toolchainInstallPath" in a Qbs file, as that path usually contains a directory with either "_32" or "_64", but Qbs couldn't read that value.

Is this the proper way to check if we are compiling for x86 or x64, and if so, do you have a way of doing it today with MinGW profiles?