There's a verse in "Blue Mountain Lake", as I recall which says:

"Bill Mitchell, ya know him, he kept our shantee
Was as mean a damn man as you ever did see;
He would lay 'round the shanty from morning to night
And if a man said a woprd he was ready to fight."

From which the meaning is clear of "shanty" as a shack for keeping tools or serving food out of. Similar usage in the expression "shanty town" for cheap poor housing...all of which has nothing to do in my mind with "chanty" which I'd be inclined to believe comes from the Latin for singing as mentioned above.

A