install ninja
$ sudo apt install ninja-dev
ubuntu build qt6 host failed：
CMake Error at /usr/lib/llvm-6.0/lib/cmake/clang/ClangTargets.cmake:496 (message): The imported target "clangBasic" references the file "/usr/lib/llvm-6.0/lib/libclangBasic.a" but this file does not exist. Possible reasons include:
because multiple version libclang installed [2]
$ sudo apt-get purge --auto-remove libclang-common-6.0-dev
ERROR: The OpenGL functionality tests failed! You might need to modify the OpenGL package search path by setting the OpenGL_DIR CMake variable to the OpenGL library's installation directory.
install opengl package [1]
$ sudo apt install libgl1-mesa-dev libglu1-mesa-dev
Reference
[2] https://github.com/CastXML/CastXML/issues/148