To build Qt (themself) with widgets for Ubuntu 24 (X11 windowing system). See also Building Qt 6.6 for Raspberry Pi on Raspberry Pi OS Tested with 22.04.3 LTS
Please switch to Xorg istead of Wayland.
Test
echo $XDG_SESSION_TYPE
Should be x11
Then make available all dev pack. For Ubuntu 24 and more new
sudo sed -i 's/^Types: deb$/Types: deb deb-src/' /etc/apt/sources.list.d/ubuntu.sources
sudo nano /etc/apt/sources.list
and uncomment all strings with "deb-src"
git clone https://github.com/AndreiCherniaev/Ubuntu_X11_Build_Qt_widgets.git
export MyBaseDir="$PWD/Ubuntu_X11_Build_Qt_widgets"
Install dependency
. "$MyBaseDir/Qt_themself/Ubuntu_dependency.sh"
Build Qt themself
"$MyBaseDir/Qt_themself/readme.sh"
export QT_DEBUG_PLUGINS=1 #usually no need, use in case of error
"$MyBaseDir/example/readme.sh"
This step is optional. If you want try to run your app with linuxfb then use
# sudo adduser $USER video
export QT_DEBUG_PLUGINS=1
# export QT_QPA_PLATFORM=linuxfb
# export QT_QPA_EGLFS_FB=/dev/fb0
"$MyBaseDir/example/readme.sh"