rt: Set the stack depth limit to 1GB. Abort on error.

People hit the recursion depth limit too often, it's not possible
to unwind reliably from out-of-stack.

Issues #3555, #3695
auto merge of #6081 : brson/rust/out-of-stack, r=thestinger

People hit the recursion depth limit too often, it's not possible
to unwind reliably from out-of-stack.

Issues #3555, #3695