temporal: try fix musl, return old code

src/unix.rs

@@ -55,7 +55,39 @@ impl Client {
 
     unsafe fn mk() -> io::Result<(Client, String)> {
         let mut pipes = [0; 2];
+
+        // Attempt atomically-create-with-cloexec if we can on Linux,
+        // detected by using the `syscall` function in `libc` to try to work
+        // with as many kernels/glibc implementations as possible.
+        #[cfg(target_os = "linux")]
+        {
+            use std::sync::atomic::{AtomicBool, Ordering};
+
+            static PIPE_AVAILABLE: AtomicBool = AtomicBool::new(true);
+            if PIPE_AVAILABLE.load(Ordering::SeqCst) {
+                match libc::syscall(libc::SYS_pipe, pipes.as_mut_ptr()) {
+                    -1 => {
+                        let err = io::Error::last_os_error();
+                        if err.raw_os_error() == Some(libc::ENOSYS) {
+                            PIPE_AVAILABLE.store(false, Ordering::SeqCst);
+                        } else {
+                            return Err(err);
+                        }
+                    }
+                    _ => {
+                        let string_arg = format!(
+                            "--jobserver-fds={},{}",
+                            pipes[0].as_raw_fd(),
+                            pipes[1].as_raw_fd()
+                        );
+                        return Ok((Client::from_fds(pipes[0], pipes[1]), string_arg));
+                    }
+                }
+            }
+        }
+
         cvt(libc::pipe(pipes.as_mut_ptr()))?;
+
         let string_arg = format!(
             "--jobserver-fds={},{}",
             pipes[0].as_raw_fd(),