What version of OR-Tools and what language are you using?
Version: master
Language: C++

What operating system (Linux, Windows, ...) and version?
Ubuntu 18.04.5 LTS (Bionic Beaver)

What did you do?
I used or-tools inside my project. I set BUILD_DEPS=ON but I did not want to install the built files.
So I set INSTALL_BUILD_DEPS=OFF, but it seems it does nothing and the installation is still happening.
(By searching INSTALL_BUILD_DEPS inside the repository, you will see nothing but the definition itself.)

What did you expect to see
By setting INSTALL_BUILD_DEPS=OFF, I expect the cmake not to install the programs.

What did you see instead?

Error like

Install the project...
-- Install configuration: "Release"
-- Installing: /usr/local/lib/libz.a
CMake Error at _deps/zlib-build/cmake_install.cmake:46 (file):
  file INSTALL cannot copy file
  "/path/to/my/build/lib/libz.a" to
  "/usr/local/lib/libz.a": Success.
Call Stack (most recent call first):
  _deps/or-tools-build/dependencies/cmake_install.cmake:47 (include)
  _deps/or-tools-build/cmake_install.cmake:47 (include)
  cmake_install.cmake:57 (include)