Version 8.4 is available upstream. Please consider updating! It seems that version 8.4 is available upstream, while the latest version in the Gentoo tree is 8.3-r1. You think this warning is false? Read more about it here.
WCSLIB is a C library, supplied with a full set of Fortran wrappers,
that implements the "World Coordinate System" (WCS) convention in FITS
(Flexible Image Transport System). It also includes a PGPLOT-based routine,
PGSBOX, for drawing general curvilinear coordinate graticules and a number of
utility programs.
Packages