adderall.internal: Stylistic fix

Use (pos?) instead of (> ... 0), thanks hydiomatic!

Signed-off-by: Gergely Nagy <algernon@madhouse-project.org>
adderall.internal: Drop defn-alias

This macro is now defined by Hy itself, no need to redefine ours over
it.

Signed-off-by: Gergely Nagy <algernon@madhouse-project.org>