qmake step does not use QMAKE_XSPEC for compilation

I created a cross compile project. The Qt version shows the correct QMAKE_SPEC and QMAKE_XSPEC in the kit management dialog. But the qmake step in the project settings uses the QMAKE_SPEC instead of QMAKE_XSPEC.

configure command:
./configure -xplatform unsupported/android-g++ -developer-build -opensource -v -no-accessibility -nomake tests -confirm-license -opengl es2 -prefix /data/user -nomake examples -nomake demos

Used Qt version shows this info in kit dialog:

Name: Qt 5.0.0 mnt
ABI:x86-linux-generic-elf-32bit
Source:/mnt/ubuntu/qt-android/qt5/qtbase
mkspec:unsupported/android-g++
qmake:/mnt/ubuntu/qt-android/qt5/qtbase/bin/qmake
Version:5.0.0
QMAKE_SPEC linux-g++-64
QMAKE_VERSION 3.0
QMAKE_XSPEC unsupported/android-g++
...

When running the compilation the compiler from linux-g+-64 is used instead of unsupported/android-g+.