maintainer-feedback requested: [Bug 265032] math/eigen3: Update to 3.4.0, add tests and cleanup

[bugzilla-noreply at freebsd.org]

Bugzilla Automation <bugzilla at FreeBSD.org> has asked freebsd-kde (Team)
<kde at FreeBSD.org> for maintainer-feedback:
Bug 265032: math/eigen3: Update to 3.4.0, add tests and cleanup
https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=265032



--- Description ---
Changes:
* add test target
* remove TEST option since it isn't needed
* change PORTVERSION to DISTVERSION
* impove Makefile format to make it more readable

3.4.0 is c++20 compatible (3.3.9 isn't).

I've tested several dependencies and they worked.
All dependencies should be tested.