minicoin is a tool designed for building and testing Qt on multiple platforms, using virtual machines that run either locally, or in the cloud.
For documentation of minicoin, see the project wiki.
$ cd ~/qt5/qtbase
$ minicoin run build ubuntu2004
$ cd ~/my_project
$ minicoin run build ubuntu2004
This will first build qtbase from the local ~/qt5/qtbase directory on the ubuntu2004 box, and then build the project in ~/my_project on the same box, using the qtbase that was built just before.