Add missing call to pthread_attr_destroy

Signed-off-by: Jens Reidel <[email protected]>

Author: Gelbpunkt

library/std/src/sys/pal/unix/thread.rs

@@ -73,6 +73,7 @@ impl Thread {
                     // on the stack size, in which case we can only gracefully return
                     // an error here.
                     if libc::pthread_attr_setstacksize(attr.as_mut_ptr(), stack_size) != 0 {
+                        assert_eq!(libc::pthread_attr_destroy(attr.as_mut_ptr()), 0);
                         drop(Box::from_raw(p));
                         return Err(io::Error::other("invalid stack size"));
                     }