[ITA] eigen3-3.3.8

[Lemures Lemniscati]

Hi!

ITA for eigen3, which have been maintained by Yaakov [1].

Now, the latest upstream version of Eigen is 3.3.8 [2].

A new candidate cygport file is placed at [3] (but it is not tested
on Cygwin AppVeyor CI, yet).

And generated package files are placed at [4] or [5].

[1]: https://cygwin.com/git/?p=git/cygwin-packages/eigen3.git
[2]: https://gitlab.com/libeigen/eigen/-/releases/
[3]: https://github.com/cygwin-lem/eigen3-cygport/tree/n_3.3.8-1
[4]: https://cygwin-lem.github.io/eigen3-cygport/
[5]: https://github.com/cygwin-lem/eigen3-cygport/tree/n_3.3.8-1_gh-pages


Regards, 

Lem