How do I override a collection path?

[koliyo]

I am trying to use the vendor collection in combination with odin installed via homebrew on my Mac.

The core collection is installed here:

/opt/homebrew/Cellar/odin/2023-02//libexec/core

But the homebrew installation does not seem to contain any vendor libraries.

Ok, so I clone the odin repository, and try specifying the vendor collection path:

odin build . -collection:vendor=$ODIN_ROOT/vendor

Then I get this error:

Library collection 'vendor' already exists with path ''

How can I specify the vendor path?