oldmap: use &K instead of K in find and get
core: sort each prelude.rs section
core: export either::{Either,Left,Right} from the prelude
core: Flesh out the either traits
Use x86-64 CABI for foreign function on arm target
automated merge
automated merge
auto merge of pull req #4777 from thestinger/rust, r=graydon
demodeing, un-gc-ing

It looks to me like the string_reader and tt_reader structs are
GC pointers only because they predate the modern borrow system.
This commit leaves the type names string_reader and tt_reader alone
(they still refer to GC-ed pointers), but internally the functions
now use borrowed pointers to refer to these structures. My guess
would be that it's possible to move this change outward and not
use the GCed pointers at all, but that change looks like it could be
a larger one. Actually, I'm delighted at how quick this change was.
lines too long