[QGIS-Developer] Custom widgets and Qt Designer 4 and 5

[matteo]

Success!!

Ok for those who can be interested, these are the steps I made:

* download and compile gdal 2.2.3 (compiled in the /opt folder)
* recompiled QGIS by changing the gdal paths and enable the flag WITH
CUSTOMWIDGET
* all went fine and QGIS is compiled against gdal 2.2.3
* in the output/lib directory there is the libqgis_customwidgets.so and
libqgis_customwidgets.so.3.1.0  files
* I copied this files to  /usr/lib/x86_64-linux-gnu/qt5/plugins/designer/

Q3 widgets are there. I still see they are saved with widget.h in the
ui, so I guess one has to change the path manually or promote the widget
like Etienne suggested

Cheers

Matteo