'Auto' footer height option

[wayfaringrob]

I don't really care how long my footer is as long as it fits all my stuff. This would apply to large, medium, and small layouts, but I see it being especially useful for small screen layouts, where it tends to 'stack' all your stuff. I have to keep going back and adjusting the height in pixels hoping it's enough/not too much. An auto setting, like that available for many layout elements, would be great.