Hi,

I attach 4 patches that correct the runtime issues freecad has and also supply some packages needed as a dependency.

Freecad is a very complex package that is hard to build because many of its dependencies' buildsystem is broken. The approach followed here is the same that Nix follows and appears to work correctly.

The changes correct the Draft module, which wasn't available because pivy was not added as a dependency.

For context, see this message:
https://lists.gnu.org/archive/html/guix-devel/2020-12/msg00123.html

Thanks