auto merge of #10965 : alexcrichton/rust/libgreen, r=brson

This pull request extracts all scheduling functionality from libstd, moving it into its own separate crates. The new libnative and libgreen will be the new way in which 1:1 and M:N scheduling is implemented. The standard library still requires an interface to the runtime, however, (think of things like `std::comm` and `io::println`). The interface is now defined by the `Runtime` trait inside of `std::rt`.

The booting process is now that libgreen defines the start lang-item and that's it. I want to extend this soon to have libnative also have a "start lang item" but also allow libgreen and libnative to be linked together in the same process. For now though, only libgreen can be used to start a program (unless you define the start lang item yourself). Again though, I want to change this soon, I just figured that this pull request is large enough as-is.

This certainly wasn't a smooth transition, certain functionality has no equivalent in this new separation, and some functionality is now better enabled through this new system. I did my best to separate all of the commits by topic and keep things fairly bite-sized, although are indeed larger than others.

As a note, this is currently rebased on top of my `std::comm` rewrite (or at least an old copy of it), but none of those commits need reviewing (that will all happen in another pull request).

2 files changed, 2 insertions, 3 deletions

diff --git a/src/libsyntax/ext/build.rs b/src/libsyntax/ext/build.rs
index 930d25e7443..aa7e0d0eced 100644
--- a/src/libsyntax/ext/build.rs
+++ b/src/libsyntax/ext/build.rs
@@ -606,7 +606,6 @@ impl AstBuilder for @ExtCtxt {
             ~[
                 self.ident_of("std"),
                 self.ident_of("rt"),
-                self.ident_of("task"),
                 self.ident_of("begin_unwind"),
             ],
             ~[
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!())
         )
     )