auto merge of #7265 : brson/rust/io-upstream, r=brson

r? @graydon, @nikomatsakis, @pcwalton, or @catamorphism

Sorry this is so huge, but it's been accumulating for about a month. There's lots of stuff here, mostly oriented toward enabling multithreaded scheduling and improving compatibility between the old and new runtimes. Adds task pinning so that we can create the 'platform thread' in servo.

[Here](https://github.com/brson/rust/blob/e1555f9b5628af2b6c6ed344cad621399cb7684d/src/libstd/rt/mod.rs#L201) is the current runtime setup code.

About half of this has already been reviewed.

1 files changed, 8 insertions, 4 deletions

diff --git a/src/rt/rust_log.cpp b/src/rt/rust_log.cpp
index df24f569495..8179c53e96d 100644
--- a/src/rt/rust_log.cpp
+++ b/src/rt/rust_log.cpp
@@ -43,11 +43,15 @@ log_console_on() {
  * overridden by the environment.
  */
 void
-log_console_off(rust_env *env) {
+log_console_off() {
     scoped_lock with(_log_lock);
-    if (env->logspec == NULL) {
-        _log_to_console = false;
-    }
+    _log_to_console = false;
+}
+
+bool
+should_log_console() {
+    scoped_lock with(_log_lock);
+    return _log_to_console;
 }
 
 rust_log::rust_log(rust_sched_loop *sched_loop) :