Ensure FindEigen3.cmake is not used

[ChrisThrasher]

Oversight from #125 since we don't test the install interface on RHEL.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 98.65%. Comparing base (4e73bb0) to head (c8a0701).

Additional details and impacted files

@@           Coverage Diff           @@
##             main     #126   +/-   ##
=======================================
  Coverage   98.65%   98.65%           
=======================================
  Files          11       11           
  Lines         223      223           
=======================================
  Hits          220      220           
  Misses          3        3           

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[ChrisThrasher]

@christophfroehlich Would you please try this out for me? If you check out main and run the tests on RHEL I suspect you'll find this bug. The unit tests install then consume the library and that tends to find issues like this. If those tests fail as expected then you can check out this branch and confirm they pass to verify this PR is correct.

[christophfroehlich]

I have RSL, generate_parameter_library, and cpp_polyfills in my workspace. With the main branch:

# colcon build
Starting >>> tcb_span
Starting >>> tl_expected               
Starting >>> generate_parameter_library_py                              
Finished <<< tl_expected [1.60s]                                                                                                 
Finished <<< generate_parameter_library_py [1.73s]                                                  
Finished <<< tcb_span [8.98s]                      
Starting >>> rsl
Finished <<< rsl [2.35s]                      
Starting >>> parameter_traits
--- stderr: parameter_traits                          
CMake Error at CMakeLists.txt:8 (find_package):
  Found package configuration file:

    /opt/ros2_ws/install/rsl/share/rsl/cmake/rsl-config.cmake

  but it set rsl_FOUND to FALSE so package "rsl" is considered to be NOT
  FOUND.  Reason given by package:

  rsl could not be found because dependency Eigen3 could not be found.
---
Failed   <<< parameter_traits [0.80s, exited with code 1]

With this fix, it builds and colcon test succeeds also. Same with downstream control_toolbox package, so I guess this fixes my workflow mentioned in #114.

Thanks again for fixing this!

[sjahr]

Thanks for the fix!