rnm@b0x (~/kde/src/kdesrc-build)
$ kdesrc-build kwindowsystem
Updating sysadmin-repo-metadata (to branch master)
        Stashing local changes if any...

Building extra-cmake-modules from frameworks (1/2)
        Updating extra-cmake-modules (to branch master)
        Stashing local changes if any...
        No changes to extra-cmake-modules source, proceeding to build.
        Compiling... succeeded (after 0 seconds)
        Installing.. succeeded (after 0 seconds)

Building kwindowsystem from frameworks (2/2)
        No source update, but the last configure failed
        Updating kwindowsystem (to branch master)
        Stashing local changes if any...
        Source update complete for kwindowsystem: no files affected
        Preparing build system for kwindowsystem.
        Removing files in build directory for kwindowsystem
        Old build system cleaned, starting new build system.
        Running cmake targeting Unix Makefiles...
        Unable to configure kwindowsystem with CMake!
        Unable to configure kwindowsystem with KDE

<<< PACKAGES SUCCESSFULLY BUILT >>>
extra-cmake-modules

Removing 1 out of 3 old log directories...

<<< PACKAGES FAILED TO BUILD >>>
kwindowsystem - ~/kde/src/log/2020-10-10-01/kwindowsystem/cmake.log

Important notification for kwindowsystem:
    kwindowsystem has failed to build 5 times.
    You can check https://build.kde.org/search/?q=kwindowsystem to see if this is expected.

:-(
Your logs are saved in file:///home/rnm/kde/src/log/2020-10-10-01

rnm@b0x (~/kde/src/kdesrc-build)
$ cat ~/kde/src/log/2020-10-10-01/kwindowsystem/cmake.log
# kdesrc-build running: 'cmake' '/home/rnm/kde/src/kwindowsystem' '-G' 'Unix Makefiles' '-DCMAKE_BUILD_TYPE=RelWithDebInfo' '-DBUILD_TESTING=TRUE' '-DCMAKE_CXX_FLAGS:STRING=-pipe' '-DCMAKE_INSTALL_PREFIX=/home/rnm/kde/usr'
# from directory: /home/rnm/kde/build/kwindowsystem
-- The C compiler identification is GNU 10.2.1
-- The CXX compiler identification is GNU 10.2.1
-- Detecting C compiler ABI info
-- Detecting C compiler ABI info - done
-- Check for working C compiler: /usr/bin/cc - skipped
-- Detecting C compile features
-- Detecting C compile features - done
-- Detecting CXX compiler ABI info
-- Detecting CXX compiler ABI info - done
-- Check for working CXX compiler: /usr/bin/c++ - skipped
-- Detecting CXX compile features
-- Detecting CXX compile features - done
-- 

Installing in /home/rnm/kde/usr. Run /home/rnm/kde/build/kwindowsystem/prefix.sh to set the environment for KWindowSystem.
-- Looking for __GLIBC__
-- Looking for __GLIBC__ - found
-- Performing Test _OFFT_IS_64BIT
-- Performing Test _OFFT_IS_64BIT - Success
-- Performing Test HAVE_DATE_TIME
-- Performing Test HAVE_DATE_TIME - Success
-- Found X11: /usr/include   
-- Looking for XOpenDisplay in /usr/lib64/libX11.so
-- Looking for XOpenDisplay in /usr/lib64/libX11.so - found
-- Looking for gethostbyname
-- Looking for gethostbyname - found
-- Looking for connect
-- Looking for connect - found
-- Looking for remove
-- Looking for remove - found
-- Looking for shmat
-- Looking for shmat - found
-- Looking for IceConnectionNumber in ICE
-- Looking for IceConnectionNumber in ICE - found
-- Found PkgConfig: /usr/bin/pkg-config (found version "1.7.3") 
-- Found XCB_XCB: /usr/lib64/libxcb.so (found version "1.13.1") 
-- Found XCB_KEYSYMS: /usr/lib64/libxcb-keysyms.so (found version "0.4.0") 
-- Found XCB_RES: /usr/lib64/libxcb-res.so (found version "1.13.1") 
-- Found XCB: /usr/lib64/libxcb.so;/usr/lib64/libxcb-keysyms.so;/usr/lib64/libxcb-res.so (found version "1.13.1") found components: XCB KEYSYMS RES 
CMake Error at /usr/lib64/cmake/Qt5/Qt5Config.cmake:28 (find_package):
  Could not find a package configuration file provided by "Qt5X11Extras" with
  any of the following names:

    Qt5X11ExtrasConfig.cmake
    qt5x11extras-config.cmake

  Add the installation prefix of "Qt5X11Extras" to CMAKE_PREFIX_PATH or set
  "Qt5X11Extras_DIR" to a directory containing one of the above files. If
  "Qt5X11Extras" provides a separate development package or SDK, be sure it
  has been installed.
Call Stack (most recent call first):
  CMakeLists.txt:69 (find_package)

-- Configuring incomplete, errors occurred!
See also "/home/rnm/kde/build/kwindowsystem/CMakeFiles/CMakeOutput.log".