[oe] building and running a qt5 application

[Trevor Woerner]

Hi,

I am trying to build and run a simple qt5 example:

    http://qt-project.org/doc/qt-5.0/qtuitools/textfinder.html

The first interesting thing that I come across is that the qt5 header
files in the sysroot are located in:

     ${PKG_CONFIG_SYSROOT_DIR}/usr/include/qt5

but when the build system configures itself to build the qt5
application, it uses a bunch of include directories such as:

    ${PKG_CONFIG_SYSROOT_DIR}/usr/include/QtCore
    ${PKG_CONFIG_SYSROOT_DIR}/usr/include/QtGui
    ${PKG_CONFIG_SYSROOT_DIR}/usr/include/QtWidgets

Therefore any recipe that wants to build a qt5 application is forced
to either modify the CXXFLAGS variable or say:

    OE_QMAKE_PATH_HEADERS = "${OE_QMAKE_PATH_QT_HEADERS}"

If the build system knows it's going to be putting the qt5 header
files in $sysroot/usr/include/qt5/etc, why not simply use that instead
of requiring the users to update the include paths themselves in all
their recipes?

Secondly, I added both "qtbase" and my package to IMAGE_INSTALL, added
the "meta-qt5" layer to "bblayers.conf", specified "QT5_VERSION" as
"5.0.2", and then built:

    $ bitbake core-image-x11

When I tried to run my application I received:

    Failed to load platform plugin "xcb". Available platforms are:

    Aborted

Shouldn't an x11 image have included the xcb platform?

Any tips on building and running a simple qt5 application in a
yocto-based image?

Best regards,
    Trevor