Fix finding of Thread libraries.

[clalancette]

Instead of include(FindThreads), use find_package(Threads), which is the correct way to do this. This removes a warning when using this with CMake >= 3.24.

Signed-off-by: Chris Lalancette clalancette@openrobotics.org

This will get rid of warnings that look like:

CMake Warning (dev) at /usr/share/cmake-3.22/Modules/FindPackageHandleStandardArgs.cmake:438 (message):
  The package name passed to `find_package_handle_standard_args` (Threads)
  does not match the name of the calling package (ecl_threads).  This can
  lead to problems in calling code that expects `find_package` result
  variables (e.g., `_FOUND`) to follow a certain pattern.
Call Stack (most recent call first):
  /usr/share/cmake-3.22/Modules/FindThreads.cmake:238 (FIND_PACKAGE_HANDLE_STANDARD_ARGS)
  /home/ubuntu/kobuki_ws/install/ecl_build/share/ecl_build/cmake/ecl_platform_detection.cmake:225 (include)
  /home/ubuntu/kobuki_ws/install/ecl_threads/share/ecl_threads/cmake/ecl_threads-extras.cmake:4 (ecl_detect_threads)
  /home/ubuntu/kobuki_ws/install/ecl_threads/share/ecl_threads/cmake/ecl_threadsConfig.cmake:41 (include)
  CMakeLists.txt:19 (find_package)
This warning is for project developers.  Use -Wno-dev to suppress it.

And should fix stonier/ecl_core#106 . @stonier FYI.

[clalancette]

Friendly ping on this one @stonier. Would be great to get this in.

[clalancette]

@stonier Another friendly ping on this one. If we merge in this and stonier/sophus#23, we can then release the kobuki nodes into Humble and Iron.