I'm not a religious person, but I consider myself to be a moral person, and morals are based on the 10 commandments. No where does it say "Thou
shalt not eat my brother (or sister) in a survival situation"!
I would never kill someone, except in self defense or the defense of my family, but if I had to under these circumstances (or someone had died by
other means), and if I (or my family) would starve otherwise, then that person is fair game for man-pie IMO!
Of course this would be a last resort, and only done under the most dire circumstances. You are effectively going back to nature, and nature has it's
own set of rules, one of which is "eat or be eaten". In 90% of situations however, I'm confident that I could find/catch some kind of food!
BTW - LOL @ apc's comment