Build projects without rpath

If I build a project in Linux, qbs compiles it with a rpath to the Qt library. I tried to deactivate this with:
cpp.rpath: undefined
in the product, but the rpath is still set

$ readelf -d executable
0x000000000000000f (RPATH) Library rpath: [$ORIGIN:/opt/qt-4.8.5/lib]

In my case, this Path exists only on the development system, the rpath must not be set!! The executable should use the default system search paths like LD_LIBRARY_PATH. How can I tell QBS to not set a rpath?

Edit:
I found a workaround, if i comment out the following lines in the share/modules/cpp/gcc.js file, no rpath is set:

if (rpaths && rpaths.length)
        args.push('-Wl,-rpath,' + rpaths.join(",-rpath,"));

maybe it's a good idea to add another property to the product module like:
property bool useRpath
and use this in the gcc.js like:

if (useRpath && rpaths && rpaths.length)
        args.push('-Wl,-rpath,' + rpaths.join(",-rpath,"));