A Neon Developer Edition live image downloaded recently from https://neon.kde.org/download (neon-developer-20190329-1357.iso), doesn't contain any development packages. This is contrary to what is stated on the download page, and the image seems to offer nothing extra compared to what would be expected in the Stable/Unstable image. Packages omitted include: - gcc - git - cmake - KDE Frameworks -dev packages - library dependency -dev packages - mariadb-server, libqt5sql5-mysql (which provide the recommended database for running Akonadi) In addition to installing all the packages listed at https://community.kde.org/Guidelines_and_HOWTOs/Build_from_source/Install_the_dependencies, I had to make apparmor allow mysqld to run.
Checking the image today https://files.kde.org/neon/images/developer/20190611-0001/neon-developer-20190611-0001.manifest it includes kde-development-environment package which depends on all the framework -dev packages I've now added build-essential and cmake as basic build tools I've also added qt dev packages. I don't think we can add every build dependency of every KDE package as that would make the image unfeasibly large. The updates will appear over the next day or two.
Thanks Jon. That's probably good enough to call this fixed.