Optionally dump stdout

ofborg/src/evalchecker.rs

@@ -28,7 +28,7 @@ impl EvalChecker {
     }
 
     pub fn execute(&self, path: &Path) -> Result<File, File> {
-        self.nix.safely(&self.cmd, path, self.args.clone())
+        self.nix.safely(&self.cmd, path, self.args.clone(), false)
     }
 
     pub fn cli_cmd(&self) -> String {

ofborg/src/nix.rs

@@ -40,18 +40,27 @@ impl Nix {
             attrargs.push(attr);
         }
 
-        return self.safely("nix-build", nixpkgs, attrargs);
+        return self.safely("nix-build", nixpkgs, attrargs, true);
     }
 
-    pub fn safely(&self, cmd: &str, nixpkgs: &Path, args: Vec<String>) -> Result<File,File> {
+    pub fn safely(&self, cmd: &str, nixpkgs: &Path, args: Vec<String>, keep_stdout: bool) -> Result<File,File> {
         let mut nixpath = OsString::new();
         nixpath.push("nixpkgs=");
         nixpath.push(nixpkgs.as_os_str());
 
-        let stdout = tempfile().expect("Fetching a stdout tempfile");
+        let stderr = tempfile().expect("Fetching a stderr tempfile");
-        let stderr = stdout.try_clone().expect("Cloning stdout for stderr");
         let mut reader = stderr.try_clone().expect("Cloning stderr to the reader");
 
+        let stdout: Stdio;
+
+        if keep_stdout {
+            let stdout_fd = stderr.try_clone().expect("Cloning stderr for stdout");
+            stdout = Stdio::from(stdout_fd);
+        } else {
+            stdout = Stdio::null();
+        }
+
+
         let status = Command::new(cmd)
             .env_clear()
             .current_dir(nixpkgs)

ofborg/src/tasks/massrebuilder.rs

@@ -436,7 +436,8 @@ impl Stdenvs {
                 String::from("."),
                 String::from("-A"),
                 String::from("stdenv"),
-            ]
+            ],
+            false
         );
 
         println!("{:?}", result);