Merge pull request #5832 from sylvestre/fuzz-pipe-stderr

fuzz: with pipe, also capture stderr

fuzz/fuzz_targets/fuzz_common.rs

@@ -232,7 +232,10 @@ pub fn run_gnu_cmd(
 
  let output = if let Some(input_str) = pipe_input {
  // We have an pipe input
- command.stdin(Stdio::piped()).stdout(Stdio::piped());
+ command
+ .stdin(Stdio::piped())
+ .stdout(Stdio::piped())
+ .stderr(Stdio::piped());
 
  let mut child = command.spawn().expect("Failed to execute command");
  let child_stdin = child.stdin.as_mut().unwrap();