I've never been in a survival situation but I have worked and played outdoors for many years , in all types of weather .
I've always worn jeans , cotton duck or cotton canvas pants .
Wool , for me , when or if I wear it , is only worn as the last layer in a layering system because I can't stand wool , even as a second layer , against my skin .
Synthetic material , for me , is not as rugged , doesn't hold up to abuse as well and isn't as comfortable as jeans or cotton duck or canvas .
My solution is to wear some type of moisture wicking underwear . In cold weather I wear microfleece long underwear . I always have an extra pair of pants in my truck in case I get wet , wich has happened many times . In fact , I always carry a complete change of clothes and extra cold weather clothes in my truck .
I think that whatever you wear - wool , synthetic or cotton - It's more important to have a base layer that will wick moisture / persperation away from your skin and always have extra clothes /socks and boots .