rustbuild: Update nightly date

Also fix a bug where we didn't clean out previous nightlies

src/bootstrap/bootstrap.py

@@ -73,6 +73,7 @@ def download_rust_nightly(self):
 
         if self.rustc().startswith(self.bin_root()) and \
            (not os.path.exists(self.rustc()) or self.rustc_out_of_date()):
+            shutil.rmtree(self.bin_root())
             filename = "rust-std-nightly-" + self.build + ".tar.gz"
             url = "https://static.rust-lang.org/dist/" + self.snap_rustc_date()
             tarball = os.path.join(rustc_cache, filename)

src/bootstrap/build/mod.rs

@@ -39,6 +39,14 @@ mod sanity;
 mod step;
 mod util;
 
+#[cfg(windows)]
+mod job;
+
+#[cfg(not(windows))]
+mod job {
+    pub unsafe fn setup() {}
+}
+
 pub use build::config::Config;
 pub use build::flags::Flags;
 
@@ -114,14 +122,9 @@ impl Build {
     pub fn build(&mut self) {
         use build::step::Source::*;
 
-        // see comments in job.rs for what's going on here
-        #[cfg(windows)]
-        fn setup_job() {
-            mod job;
-            unsafe { job::setup() }
+        unsafe {
+            job::setup();
         }
-        #[cfg(not(windows))] fn setup_job() {}
-        setup_job();
 
         if self.flags.clean {
             return clean::clean(self);

src/nightlies.txt

@@ -1,2 +1,2 @@
-rustc: 2015-12-19
+rustc: 2016-02-17
 cargo: 2016-01-21