Update mod.rs

Co-authored-by: Alphyr <[email protected]>

Author: NobodyXu

library/std/src/sys/anonymous_pipe/mod.rs

@@ -10,7 +10,7 @@ pub fn pipe() -> io::Result<(PipeReader, PipeWriter)> {
         } else if #[cfg(windows)] {
             windows::pipe()
         } else {
-            panic!("Anonymous pipe is not supported on this target!")
+            Err(io::Error::UNSUPPORTED_PLATFORM)
         }
     }
 }