[Qgis-developer] Compiling QGIS3 with Qt5.8.0 RC - Ubuntu 16.04 64 bit

[gordon at shieldaig.com]

Is there a simple way to do this?

I set Qt Creator to use a local version.
`qtchooser -install -local 5.8 /home/gordon/Qt/5.8/gcc_64/bin/qmake`

And the environment I would like to use for development like this:
`qtchooser -print-env`
`QT_SELECT="5.8"`
`QTTOOLDIR="/home/gordon/Qt/5.8/gcc_64/bin"`
`QTLIBDIR="/home/gordon/Qt/5.8/gcc_64/lib"`

Except I see no easy way to have `cmake ..` find my local package as it 
uses the ones from the Ubuntu 16.04 Qt5 development defaults package.