Use computed relative extras path

[scpeters]

🦟 Bug fix

Needed by gazebosim/gz-transport#398, follow-up to gazebosim/gz-cmake#360 and #339 (comment)

Summary

Use PROJECT_CMAKE_EXTRAS_INSTALL_DIR and PROJECT_CMAKE_EXTRAS_PATH_TO_PREFIX to improve support for arch-dependent lib folders. In particular, the fixed relative path ../../.. is incorrect when installing to /usr on debian systems, so the computed relative path PROJECT_CMAKE_EXTRAS_PATH_TO_PREFIX is used instead. Also install the other cmake extras to PROJECT_CMAKE_EXTRAS_INSTALL_DIR.

Checklist

• Signed all commits for DCO
• Added tests
• Updated documentation (as needed)
• Updated migration guide (as needed)
• Consider updating Python bindings (if the library has them)
• codecheck passed (See contributing)
• All tests passed (See test coverage)
• While waiting for a review on your PR, please help review another open pull request to support the maintainers

Note to maintainers: Remember to use Squash-Merge and edit the commit message to match the pull request summary while retaining Signed-off-by messages.

[codecov]

Codecov Report

Merging #359 (c6ebe78) into main (16de9ef) will not change coverage.
The diff coverage is n/a.

❗ Current head c6ebe78 differs from pull request most recent head ab34acf. Consider uploading reports for the commit ab34acf to get more accurate results

@@           Coverage Diff           @@
##             main     #359   +/-   ##
=======================================
  Coverage   96.89%   96.89%           
=======================================
  Files          28       28           
  Lines        1064     1064           
=======================================
  Hits         1031     1031           
  Misses         33       33           

[scpeters]

the homebrew build is passing because of the changes in the following branch:

• osrf/homebrew-simulation@master...ci_matching_branch/cmake_extras_install

we'll need to make a gz-cmake3 release in order to keep homebrew working

[scpeters]

CI is happy now that gazebosim/gz-cmake#362 is merged and new nightlies have been built

[j-rivero]

We are using in this PR new gz-cmake variables introduced in gazebosim/gz-cmake#362 if I'm not wrong. If that is the case, we are going to need a version requirement in the find_package(gz-cmake) to be sure that the system has a compatible gz-cmake package and does not resolve variables as empty. We probably need to bump gz-cmake to 3.3.0.

[j-rivero]

Use PROJECT_CMAKE_EXTRAS_INSTALL_DIR and PROJECT_CMAKE_EXTRAS_PATH_TO_PREFIX to improve support for arch-dependent lib folders. In particular

As a side note, if we are going to use these variables exported from GzConfigureProject we should document it well somehow.

[scpeters]

Use PROJECT_CMAKE_EXTRAS_INSTALL_DIR and PROJECT_CMAKE_EXTRAS_PATH_TO_PREFIX to improve support for arch-dependent lib folders. In particular

As a side note, if we are going to use these variables exported from GzConfigureProject we should document it well somehow.

this is a great point. We are currently documenting only some of the input parameters to GzConfigureProject, but none of the output parameters. I'll see if I can whip up something quick for this file in preparation for a 3.3.0 release

[scpeters]

Use PROJECT_CMAKE_EXTRAS_INSTALL_DIR and PROJECT_CMAKE_EXTRAS_PATH_TO_PREFIX to improve support for arch-dependent lib folders. In particular

As a side note, if we are going to use these variables exported from GzConfigureProject we should document it well somehow.

this is a great point. We are currently documenting only some of the input parameters to GzConfigureProject, but none of the output parameters. I'll see if I can whip up something quick for this file in preparation for a 3.3.0 release

@j-rivero I've started on the documentation in gazebosim/gz-cmake#364; please let me know what you think

[scpeters]

@osrf-jenkins run tests please