The rehash process will now discover executables in additional locations:
- `~/.gem/ruby/<version>/bin/*`
- `$GEM_HOME/bin`
The `rbenv which` (and thus `rbenv exec`) command will also search these locations when looking up a command. This enables shims to dispatch calls to executables added by `gem install --user-install`.
Note that this support is limited:
- It will only work with C Ruby, as it's difficult to guess the `~/.gem/<engine>/<version>` directory for other Rubies without actually loading Ruby;
- It will only work for RBENV_VERSION values in the format `X.Y.Z` and not "system".