Two reasons for this:
- more fine-grained space/functionality tradeoff
- preparation for the sage 8.6 update, which finally doesn't need a
downgraded gap anymore but does break when unexpected (non-standard)
packages are installed. Details: https://trac.sagemath.org/ticket/26983
The proper way to deal with gap packages would be to create a package
set, package each one individually and have something like gap
equivalent of `python.withPackages`. I am not willing to do that
however.
There are some starts of a `make install`, but nothing complete yet.
Upstream now ships a `libgap` as a replacement of the custom one used by
sagemath.
