AMF's out.
It's an emination from the caster. Can't gift it away, unless the troll's really good with UMD and they've got a scroll handy.
Death Ward only works against [Death] effects and negative energy effects.
Spell Resistance and Spell Immunity would work as normal. They're both cleric spells, though, and Spell Immunity only works on spells of 4th lvl or lower - won't stop most of the things that would bypass regen anyway. Greater Spell Immunity would, but it's an 8th lvl cleric spell.. and if you have an illithid that can toss around 8th level cleric spells, you've got bigger issues than just buffed wartrolls. Also the durations are a factor: 1 min/lvl for Spell Resistance, 10 min/lvl for Spell Immunity. They're not all-day spells. If they show up, that means whomever did the buffing A) knows you're on the way, and B) is somewhere in the area. Neither are exactly pleasant thoughts when it comes to mind flayers.