avoid stdout redirection on curl executions

src/bootstrap/bootstrap.py

@@ -104,16 +104,15 @@ def _download(path, url, probably_big, verbose, exception):
         # If curl is not present on Win32, we should not sys.exit
         #   but raise `CalledProcessError` or `OSError` instead
         require(["curl", "--version"], exception=platform_is_win32())
-        with open(path, "wb") as outfile:
-            run(["curl", option,
-                "-L", # Follow redirect.
-                "-y", "30", "-Y", "10",    # timeout if speed is < 10 bytes/sec for > 30 seconds
-                "--connect-timeout", "30",  # timeout if cannot connect within 30 seconds
-                "--retry", "3", "-SRf", url],
-                stdout=outfile,    #Implements cli redirect operator '>'
-                verbose=verbose,
-                exception=True, # Will raise RuntimeError on failure
-            )
+        run(["curl", option,
+            "-L", # Follow redirect.
+            "-y", "30", "-Y", "10",    # timeout if speed is < 10 bytes/sec for > 30 seconds
+            "--connect-timeout", "30",  # timeout if cannot connect within 30 seconds
+            "-o", path,
+            "--retry", "3", "-SRf", url],
+            verbose=verbose,
+            exception=True, # Will raise RuntimeError on failure
+        )
     except (subprocess.CalledProcessError, OSError, RuntimeError):
         # see http://serverfault.com/questions/301128/how-to-download
         if platform_is_win32():

src/bootstrap/download.rs

@@ -216,6 +216,8 @@ impl Config {
             "10", // timeout if speed is < 10 bytes/sec for > 30 seconds
             "--connect-timeout",
             "30", // timeout if cannot connect within 30 seconds
+            "-o",
+            tempfile.to_str().unwrap(),
             "--retry",
             "3",
             "-SRf",
@@ -227,8 +229,6 @@ impl Config {
             curl.arg("--progress-bar");
         }
         curl.arg(url);
-        let f = File::create(tempfile).unwrap();
-        curl.stdout(Stdio::from(f));
         if !self.check_run(&mut curl) {
             if self.build.contains("windows-msvc") {
                 eprintln!("Fallback to PowerShell");