The replacement for PGPlot is an interface layer called PG2PLplot that takes the PGPlot API and converts it into calls to PLPlot which is a LGPL, unencumbered system. The problem with conversion is that it doesn't convert everything, but getting it to convert everything and fixing the interface problems should about a month. In addition to the copyright issues, there seems to have been no development on PGPlot in over a decade, whereas PLplot is being actively developed.
Since Starlink has a special exception for PGplot, I'll work first on getting it packaged and I should be able to do it before the 10/15 version freeze deadline for Mageia. Once its packaged I'll work next on getting it working with the PG2PLplot interface layer.