I am trying to create a CMakeLists.txt file for a project that requires Eigen.
A complication is that I would like this CMake build to work in the cases where
Eigen has been installed and when it has simply been unpacked into a directory
tree (this is the way I normally use Eigen).
But it appears to me that this approach works only for the installed case because
Eigen3Config.cmake doesn't exist until Eigen is installed.
On the other hand, the un-installed Eigen source tree contains the file FindEigen3.cmake
which can be found by cmake find_package in module mode. But FindEigen3.cmake
isn't copied to the directory tree by the installation process.
As a consequence, my CMakeLists.txt file requires some rather convoluted logic
to support both cases. Am I understanding the current situation correctly?