Follow-up from #29706.
We get rid of the use of uname_specific to define an Extension option in module_list, replacing it by use of cython_aliases.
Depends on #29706
CC:  @kliem @kiwifb @dimpase @orlitzky
Component: refactoring
Author: Matthias Koeppe
Branch/Commit: 2ba1d7b
Reviewer: Jonathan Kliem
Issue created by migration from https://trac.sagemath.org/ticket/29785