Installed module library can't find imported headers [Ubuntu 22.04 LTS, CMake 3.28.1, Ninja 1.11.1 and Clang 17.0.6]

@ben.boeckel It does still not work on OSX. What is different on Apple?

bash-5.2$ find stagedir/include -name gtest.h
stagedir/include/gtest/internal/custom/gtest.h
stagedir/include/gtest/gtest.h

bash-5.2$ ll stagedir/lib/cmake/GTest/*.cmake
-rw-r--r-- 1 clausklein 5.3K Feb 24 22:21 stagedir/lib/cmake/GTest/GTestTargets.cmake
-rw-r--r-- 1 clausklein 2.3K Feb 24 22:21 stagedir/lib/cmake/GTest/GTestTargets-release.cmake
-rw-r--r-- 1 clausklein 1.9K Feb 24 22:21 stagedir/lib/cmake/GTest/GTestConfigVersion.cmake
-rw-r--r-- 1 clausklein 1.1K Feb 24 22:21 stagedir/lib/cmake/GTest/GTestConfig.cmake

bash-5.2$ cmake --version
cmake version 3.28.3
CMake suite maintained and supported by Kitware (kitware.com/cmake).

bash-5.2$ clang --version
Homebrew clang version 17.0.6
Target: x86_64-apple-darwin23.3.0
Thread model: posix
InstalledDir: /usr/local/opt/llvm/bin

bash-5.2$