math/atlas: upgrade to 3.10.3
The development iof ATLAS seems stalled, but some people still use it:
upgrade it to the latest stable version, to support some more platforms.
Changelog available from
https://sourceforge.net/projects/math-atlas/files/Stable/3.10.3/ChangeLog/download.
Next step: resurrect atlas-devel and upgrade it to the latest "unstable
release", 3.11.41, dated 2018-10-05…