green: Rip the bandaid off, introduce libgreen

This extracts everything related to green scheduling from libstd and introduces
a new libgreen crate. This mostly involves deleting most of std::rt and moving
it to libgreen.

Along with the movement of code, this commit rearchitects many functions in the
scheduler in order to adapt to the fact that Local::take now *only* works on a
Task, not a scheduler. This mostly just involved threading the current green
task through in a few locations, but there were one or two spots where things
got hairy.

There are a few repercussions of this commit:

* tube/rc have been removed (the runtime implementation of rc)
* There is no longer a "single threaded" spawning mode for tasks. This is now
  encompassed by 1:1 scheduling + communication. Convenience methods have been
  introduced that are specific to libgreen to assist in the spawning of pools of
  schedulers.

1 files changed, 2 insertions, 2 deletions

diff --git a/src/libsyntax/ext/expand.rs b/src/libsyntax/ext/expand.rs
index a6e45c7e1bb..2c2669e914c 100644
--- a/src/libsyntax/ext/expand.rs
+++ b/src/libsyntax/ext/expand.rs
@@ -740,10 +740,10 @@ pub fn std_macros() -> @str {
             fail!("explicit failure")
         );
         ($msg:expr) => (
-            ::std::rt::task::begin_unwind($msg, file!(), line!())
+            ::std::rt::begin_unwind($msg, file!(), line!())
         );
         ($fmt:expr, $($arg:tt)*) => (
-            ::std::rt::task::begin_unwind(format!($fmt, $($arg)*), file!(), line!())
+            ::std::rt::begin_unwind(format!($fmt, $($arg)*), file!(), line!())
         )
     )