rpath for Qt libraries should not contain sysroot when cross-building

Building a Qt application for embedded linux using a linux host computer, my Qbs profile has the qbs.sysroot property set:

/my/toolchain/sysroot

The Qt libraries used are placed in

/my/toolchain/sysroot/opt/qt/lib

When building this, the binary has the following rpath set automatically:

/my/toolchain/sysroot/opt/qt/lib

This makes no sense on the target device, and should rather have been stripped of the sysroot path so that the rpath we get is:

rpath: /opt/qt/lib