umbrello: file cannot create directory: /qch. Maybe need administrative privileges.

The latest release as well as master of umbrello tries to install qch files to /qch. Full log is here, while most important part is:

CMake Error at cmake_install.cmake:49 (file):
  file cannot create directory: /qch.  Maybe need administrative privileges.


FAILED: CMakeFiles/install.util 
cd /tmp/umbrello-20200928-53058-pdjdvm/build && /usr/local/Cellar/cmake/3.18.3/bin/cmake -P cmake_install.cmake
ninja: build stopped: subcommand failed.

What I had tried:

1. -DBUILD_QCH=OFF
2. -DQCHDIR=doc/qch -DQTQCHDIR=doc/qch
3. Combining first two options.