Co-authored-by: Justin Bedo <cu@cua0.org>
Co-authored-by: Jonathan Ringer <jonringer@users.noreply.github.com>
Co-authored-by: Sandro <sandro.jaeckel@gmail.com>
Co-authored-by: Benjamin Darwin <bcdarwin@gmail.com>
This attempts to fix the issue described at
https://github.com/NixOS/nixpkgs/pull/22219#issuecomment-291801133.
Any change to the custom packages passed to RStudio causes this to
completely rebuild RStudio, which is completely unnecessary and also a
bit of a hindrance as it's a fairly slow build.
This rolls back most of that old PR, and instead implements something
more like rWrapper. Existing configurations with the old useRPackages
will break.
