Auto merge of #38353 - alexcrichton:fix-nightiles, r=alexcrichton

Another round of nightly fixes

Another three separate errors happened last night:

* Race condition in save analysis failed the OX build
* Packaging docs that don't exist failed the Android build
* Packaging save-analysis that doesn't exist failed the cross host builds

It just never ends...

src/bootstrap/dist.rs

@@ -48,6 +48,11 @@ pub fn tmpdir(build: &Build) -> PathBuf {
 /// Slurps up documentation from the `stage`'s `host`.
 pub fn docs(build: &Build, stage: u32, host: &str) {
     println!("Dist docs stage{} ({})", stage, host);
+    if !build.config.docs {
+        println!("\tskipping - docs disabled");
+        return
+    }
+
     let name = format!("rust-docs-{}", package_vers(build));
     let image = tmpdir(build).join(format!("{}-{}-image", name, name));
     let _ = fs::remove_dir_all(&image);
@@ -260,6 +265,14 @@ pub fn debugger_scripts(build: &Build,
 pub fn std(build: &Build, compiler: &Compiler, target: &str) {
     println!("Dist std stage{} ({} -> {})", compiler.stage, compiler.host,
              target);
+
+    // The only true set of target libraries came from the build triple, so
+    // let's reduce redundant work by only producing archives from that host.
+    if compiler.host != build.config.build {
+        println!("\tskipping, not a build host");
+        return
+    }
+
     let name = format!("rust-std-{}", package_vers(build));
     let image = tmpdir(build).join(format!("{}-{}-image", name, target));
     let _ = fs::remove_dir_all(&image);
@@ -294,10 +307,15 @@ pub fn analysis(build: &Build, compiler: &Compiler, target: &str) {
     println!("Dist analysis");
 
     if build.config.channel != "nightly" {
-        println!("Skipping dist-analysis - not on nightly channel");
+        println!("\tskipping - not on nightly channel");
         return;
     }
+    if compiler.host != build.config.build {
+        println!("\tskipping - not a build host");
+        return
+    }
     if compiler.stage != 2 {
+        println!("\tskipping - not stage2");
         return
     }
 

src/librustc_save_analysis/lib.rs

@@ -48,7 +48,7 @@ use rustc::session::config::CrateType::CrateTypeExecutable;
 use rustc::ty::{self, TyCtxt};
 
 use std::env;
-use std::fs::{self, File};
+use std::fs::File;
 use std::path::{Path, PathBuf};
 
 use syntax::ast::{self, NodeId, PatKind, Attribute, CRATE_NODE_ID};
@@ -832,7 +832,7 @@ pub fn process_crate<'l, 'tcx>(tcx: TyCtxt<'l, 'tcx, 'tcx>,
         },
     };
 
-    if let Err(e) = fs::create_dir_all(&root_path) {
+    if let Err(e) = rustc::util::fs::create_dir_racy(&root_path) {
         tcx.sess.err(&format!("Could not create directory {}: {}",
                               root_path.display(),
                               e));