Even on platforms that don't have the new git version, yet.
And using the convoluted way to create an environment variable that should
point to our checked out tree in the GitHub Action. The more obvious ways
have resulted in failed builds for obscure reasons.
Signed-off-by: Dirk Hohndel <dirk@hohndel.org>
Android and iOS use qmake, so add the code to the .pro file.
This also removes all remnants of QCharts includes and uses and all the
references to QCharts in our various build systems.
That was a brief but extremely useful detour.
Signed-off-by: Dirk Hohndel <dirk@hohndel.org>