Replace exec_program calls (not working out of the box in CMake 3.28)

[j-rivero]

🦟 Bug fix

Summary

exec_program calls start to fail unless a given policy is set in CMake starting with Cmake 3.28 (the version in Noble). Replace the existing calls.

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)
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[azeey]

I made similar changes in #402. I should have backported it. I think the way RESULT_VARIABLE is handled was a little tricky. Have you tried running make uninstall?

[j-rivero]

I made similar changes in #402. I should have backported it.

Oh I missed it.

I think the way RESULT_VARIABLE is handled was a little tricky. Have you tried running make uninstall?

I haven't. I was forwarding the changed made in Debian to ign-cmake2 by other user and only did a visual inspection but did not run any code. I'll take care of backporting #402