Can not build Qt from sources

Qt6.1.0 beta3 source archive extracted. Have cmake and ninja in path and set
LLVM_INSTALL_DIR=/opt/libclang/
export CMAKE_GENERATOR=Ninja

Run
cmake -DCMAKE_C_COMPILER=gcc -DCMAKE_CXX_COMPILER=g++ -DBUILD_EXAMPLES=OFF -DOPENSSL_ROOT_DIR=/opt/openssl-1.1.1g -DCMAKE_BUILD_TYPE=Release -DFEATURE_system_jpeg=OFF -DFEATURE_system_png=OFF -DFEATURE_system_pcre2=OFF -DFEATURE_system_harfbuzz=OFF -DFEATURE_system_doubleconversion=OFF -DFEATURE_libudev=OFF -DBUILD_TESTING=OFF /home/johanna/Qt/src-6.1.0-beta3 -DCMAKE_INSTALL_PREFIX:PATH=/home/johanna/Qt/src-6.1.0-beta3/qtbase

Fails with:

CMake Error:
  Running
   '/home/johanna/Qt/Tools/Tools/Ninja/ninja' '-C' '/home/johanna/Qt/src-6.1.0-beta3' '-t' 'recompact'
  failed with:
   ninja: error: build.ninja:59377: multiple rules generate qtbase/qml/Qt3D/Core/plugins.qmltypes [-w dupbuild=err]