qmake: make uninstall tries to remove system folders containing files installed with INSTALLS

Question

This is my .pro file:

TEMPLATE = app
TARGET = myapp
INCLUDEPATH += .

win32 {
    RC_FILE = win32/myapp.rc
}

unix {
    target.path = /usr/share/myapp/
    shortcutfiles.files += unix/myapp.desktop
    shortcutfiles.path = /usr/share/applications/
    data.files += unix/myapp.png
    data.path = /usr/share/pixmaps/
    INSTALLS += target
    INSTALLS += shortcutfiles
    INSTALLS += data
}

SOURCES += myapp.cpp
QT += webkitwidgets

RESOURCES += \
    myapp.qrc

Under linux, the make uninstall command, while removing the actual installed files and folder, tries to remove the /usr/share/applications/ and /usr/share/pixmaps/ folders (with rmdir); and because they are not empty folders it fails with error code 1 (ignored actually).

How to modify my .pro file to prevent make uninstall from trying to remove those system folders?

Thanks.