rustcMaster: Fix test_override_env and enable tests

We also need to disable parallel building due to rust-lang/rust#16305.

Closes NixOS#4339

Author: wizeman

pkgs/development/compilers/rustc/head.nix

@@ -1,4 +1,6 @@
-{stdenv, fetchurl, fetchgit, which, file, perl, curl, python27, makeWrapper}:
+{ stdenv, fetchurl, fetchgit, which, file, perl, curl, python27, makeWrapper
+, tzdata, git
+}:
 
 assert stdenv.gcc.gcc != null;
 
@@ -63,14 +65,19 @@ in stdenv.mkDerivation {
   configureFlags = [ "--enable-local-rust" "--local-rust-root=$snapshot" ];
 
   # The compiler requires cc, so we patch the source to tell it where to find it
-  patches = [ ./hardcode_paths.HEAD.patch ./local_stage0.HEAD.patch ];
+  patches = [ ./hardcode_paths.HEAD.patch ./local_stage0.HEAD.patch ./override_env.HEAD.patch ];
   postPatch = ''
     substituteInPlace src/librustc/back/link.rs \
       --subst-var-by "ccPath" "${stdenv.gcc}/bin/cc"
     substituteInPlace src/librustc_back/archive.rs \
       --subst-var-by "arPath" "${stdenv.gcc.binutils}/bin/ar"
   '';
 
-  buildInputs = [ which file perl curl python27 makeWrapper ];
-  enableParallelBuilding = true;
+  buildInputs = [ which file perl curl python27 makeWrapper git ];
+
+  enableParallelBuilding = false; # disabled due to rust-lang/rust#16305
+
+  preCheck = "export TZDIR=${tzdata}/share/zoneinfo";
+
+  doCheck = true;
 }

pkgs/development/compilers/rustc/override_env.HEAD.patch

@@ -0,0 +1,39 @@
+commit 02f4c61bd6a2aedbf56169aff5b3a65c83c89557
+Author: Ricardo M. Correia <[email protected]>
+Date:   Tue Sep 30 15:57:06 2014 +0200
+
+    libstd: Pass-through PATH in test_override_env test
+    
+    In some operating systems (such as NixOS), `env` can only be found in
+    the explicitly-provided PATH, not in default places such as /bin or
+    /usr/bin. So we need to pass-through PATH when spawning the `env`
+    sub-process.
+
+diff --git a/src/libstd/io/process.rs b/src/libstd/io/process.rs
+index 83890d2..8fbf254 100644
+--- a/src/libstd/io/process.rs
++++ b/src/libstd/io/process.rs
+@@ -956,7 +956,22 @@ mod tests {
+     })
+ 
+     iotest!(fn test_override_env() {
+-        let new_env = vec![("RUN_TEST_NEW_ENV", "123")];
++        use os;
++        let mut new_env = vec![("RUN_TEST_NEW_ENV", "123")];
++
++        // In some operating systems (such as NixOS), `env` can only be found in
++        // the explicitly-provided PATH env variable, not in default places
++        // such as /bin or /usr/bin. So we need to pass through PATH to our
++        // sub-process.
++        let path_val: String;
++        match os::getenv("PATH") {
++            None => {}
++            Some(val) => {
++                path_val = val;
++                new_env.push(("PATH", path_val.as_slice()))
++            }
++        }
++
+         let prog = env_cmd().env_set_all(new_env.as_slice()).spawn().unwrap();
+         let result = prog.wait_with_output().unwrap();
+         let output = String::from_utf8_lossy(result.output.as_slice()).into_string();