parse transform options

How do you pass options (2nd argument) to a parse transform?

Documentation (http://erlang.org/doc/man/erl_id_trans.html#parse_transform-2)
states that a custom parse transform module should export function that
takes two parameters:

parse_transform(Tree, Options) ->
   ...


but there doesn't seem to be a way to pass the transform options from the
compiler, i.e.:

erlc +'{parse_transform,Module}' File.erl


What am I missing?