Although kdesrc-build supports building Qt5 just like the KDE Frameworks, I prefer to use the prebuilt Qt binaries from qt.io for testing against alpha and beta releases. This saves me a lot of time on my machine, which is not powerful enough to compile the full Qt in a reasonable time.
This guide assumes that you already installed Qt from qt.io/download-qt-installer.
To reproduce my setup, an additional step is required compared to a kdesrc-build setup that uses the system Qt, nevertheless you start as usual, by cloning kdesrc-build itself:
git clone https://invent.kde.org/kde/kdesrc-build
Since kdesrc-build should be available anywhere on the system, not just in its own directory, we add it to the PATH variable by appending export PATH=~/kde/src/kdesrc-build:$PATH to your .profile file.
Please remember to adapt the path according to where you cloned kdesrc-build to.
echo "export PATH=~/kde/src/kdesrc-build:$PATH" >> ~/.profile
source ~/.profile
Next, the initial setup needs to be performed:
kdesrc-build --initial-setup
This step created all the required configuration files, which now need slight adaptions in order to work with the Qt we downloaded from qt.io in the beginning.
Edit ~/.kdesrc-buildrc, and replace the path to Qt qtdir with the path you installed Qt to.
The line should then look similar to this:
qtdir ~/.local/Qt/5.13.0/gcc_64 # Where to find Qt5
Now as a final step we need to prevent kdesrc-build from trying to build its own Qt, which can be done by commenting one include line:
include /home/jbb/kde/kdesrc-build/qt5-build-include, so it looks like #include /home/jbb/kde/kdesrc-build/qt5-build-include.
This should be it! Have fun compiling up to date KDE software using an up to date Qt without compiling Qt for hours :)
kdesrc-build kirigami --include-dependencies
To activate your newly created environment, you can use
source ~/.config/kde-env-master.sh