Fix the exportsQbs autotest for mingw
Fix the exportsQbs autotest for mingw

Fun fact: If the file path you pass to the linker via -o does not
contain a dot, then mingw will append ".exe".

Change-Id: I4a4133c99fc63fd91e47c905ca902d3eb26b1146
Reviewed-by: Joerg Bornemann <47777b9406dbddd02a3fdca8341789a013805a11@qt.io>

qtproject/qt-labs-qbs,qt-labs/qbs,qt-labs/qbs,qt-labs/qbs,qt-labs/qbs,qtproject/qt-labs-qbs,qtproject/qt-labs-qbs,qtproject/qt-labs-qbs,qt-labs/qbs,qtproject/qt-labs-qbs,qt-labs/qbs,qtproject/qt-labs-qbs,qt-labs/qbs,qtproject/qt-labs-qbs