Idris packaging

[P]

I ran across an idiosyncrasy in Idris's module system, it looks like 
`IDRIS_LIBRARY_PATH` is not a list of colon separated paths but a single path, 
but it supports multiple source and binary paths with the `--sourcepath` 
option. Currently this breaks `guix environment` if Idris is installed in the 
user's profile.

Should I patch Idris itself to use a list of paths in `IDRIS_LIBRARY_PATH` or 
should I create a wrapper that calls it with `--sourcepath`?