A174: (FRCS 23)
Mielikki, who is famous for the number of druid/rangers who
worship her, has more lenient spiritual oaths than most deities
that druids worship in the Realms. Druids of Mielikki can use
any of the standard armor or weapons that rangers normally use
(all simple and martial weapons, all light and medium armor,
and all shields) without violating their spiritual oaths.
Edit: Hmm, this does not actually grant proficiency.
Edit: Be an outsider. Take feat Weapon Proficiency (Greatclub). Dip fighter.