Beforehand it was assumed that the standard cdecl abi was used for all extern
fns of extern crates, but this reads the abi of the extern fn type and declares
the function in the local crate with the appropriate type.

r? @metajack - This solves the problem you were having earlier with things like ```extern mod geom = "rust-geom";``` (or something like that).

For some reason, I thought it wasn't necessary to write the package_id
attribute (which rustc's filesearch checks when searching for a package)
if the package ID had a single component (like "foo") as opposed to multiple
components (like "foo/bar/quux"). This meant that
`extern mod quux = "an-awesome-library";` didn't work, even if an-awesome-library
existed in the RUST_PATH.

Fixed it.

My focus was on getting these to be correct in all cases by handling overflow properly. I'll clean them up and work on the performance later.

SharedPort implementation was missing in std::comm. Since this module
also wraps SharedChan, it makes sense to have SharedPort defined there
as well.

Allows `std::rt::io::timer::sleep(1000)` rather than `std::rt::io::timer::Timer::new().unwrap().sleep(1000)`.

SharedPort implementation was missing in std::comm. Since this module
also wraps SharedChan, it makes sense to have SharedPort defined there
as well.

Closes #5794

Somehow this was missed!

cc #4819

I'm getting the three `make check` failures mentioned in issue #9127, which I also get building master.

Work a bit towards #9157 "Remove Either". These instances don't need to use Either and are better expressed in other ways (removing allocations and simplifying types).

An expression such as `bottom == not_bottom` or `not_bottom == bottom`
already compiled, but this fixes the case where both sides are `bottom`.

It was broken on win32 because of header inconsistency.

Closes #9123

Remove references to local_data::Key and only mention the macro for how to
construct new keys into local data.

This is a workaround for #9155. Currently, any uses of BufferedStream
outside of libstd ICE.

This is a series of patches to modernize option and result. The highlights are:

* rename `.unwrap_or_default(value)` and etc to `.unwrap_or(value)`
* add `.unwrap_or_default()` that uses the `Default` trait
* add `Default` implementations for vecs, HashMap, Option
* add  `Option.and(T) -> Option<T>`, `Option.and_then(&fn() -> Option<T>) -> Option<T>`, `Option.or(T) -> Option<T>`, and `Option.or_else(&fn() -> Option<T>) -> Option<T>`
* add `option::ToOption`, `option::IntoOption`, `option::AsOption`, `result::ToResult`, `result::IntoResult`, `result::AsResult`, `either::ToEither`, and `either::IntoEither`, `either::AsEither`
* renamed `Option::chain*` and `Result::chain*` to `and_then` and `or_else` to avoid the eventual collision with `Iterator.chain`.
* Added a bunch of impls of `Default`
* Added a `#[deriving(Default)]` syntax extension
* Removed impls of `Zero` for `Option<T>` and vecs. 

While usage of change_dir_locked is synchronized against itself, it's not
synchronized against other relative path usage, so I'm of the opinion that it
just really doesn't help in running tests. In order to prevent the problems that
have been cropping up, this completely removes the function.

All existing tests (except one) using it have been moved to run-pass tests where
they get their own process and don't need to be synchronized with anyone else.

There is one now-ignored rustpkg test because when I moved it to a run-pass test
apparently run-pass isn't set up to have 'extern mod rustc' (it ends up having
linkage failures).

While usage of change_dir_locked is synchronized against itself, it's not
synchronized against other relative path usage, so I'm of the opinion that it
just really doesn't help in running tests. In order to prevent the problems that
have been cropping up, this completely removes the function.

All existing tests (except one) using it have been moved to run-pass tests where
they get their own process and don't need to be synchronized with anyone else.

There is one now-ignored rustpkg test because when I moved it to a run-pass test
apparently run-pass isn't set up to have 'extern mod rustc' (it ends up having
linkage failures).

Servo is hitting this problem, so this is a workaround for lack of a real solution.

No tests because I couldn't actually reproduce the problem with either of the testcases in #9129

Closes #5794

Using an enum with two cases for `Work` reveals simpler code than the
previous `Option<Either<X, Y>>` representation.

OptRes was combining a successful value with an error message, which
fits the Result type perfectly.

The arg or capture type alias was actually never used for the capture
case, so the code is simplified with `Either<arg, ()>` replaced by `arg`

This was intended to always use inbounds pointer arithmetic now.

Servo is hitting this problem, so this is a workaround for a lack of a real solution.

An expression such as `bottom == not_bottom` or `not_bottom == bottom`
already compiled, but this fixes the case where both sides are `bottom`.