I am using QtCreator on Ubuntu for application development in C++. I recently upgraded my Ubuntu from 19.10 to 20.04 and now have problems with the IDE (or so it seems...):
- Building the code still works BUT:
- QtCreator complains that stddef.h could not be found (included from <QtCore>)
- the IDE does not seem to to be familiar with namespace std::
- the previously working includes for gstreamer do not work (in the IDE context, compiling and linking do work...) anymore

Does anyone have any hints on fixing this for Ubuntu 20.04 LTS?