Version 2019.05.21 is available upstream. Please consider updating!
It seems that version 2019.05.21 is available upstream, while the latest version in the Gentoo tree is 2015.06.23. You think this warning is false? Read more about it here.
HSL (formerly the Harwell Subroutine Library) is a collection of
state-of-the-art packages for large-scale scientific computation
such as the solution of sparse linear systems of equations and
sparse eigenvalue problems. This package is specific as a plugin for
Ipopt.