Fix build on macOS which doesn't have separate 32-bit dirent (#2492)

Author: kornelski

tests/randomize_readdir/src/lib.rs

@@ -42,7 +42,11 @@
 //! not defined, which is not ideal.
 
 use ctor::ctor;
-use libc::{c_char, c_int, c_void, dirent, dirent64, dlsym, DIR, RTLD_NEXT};
+#[cfg(target_vendor = "apple")]
+use libc::dirent as dirent64;
+#[cfg(not(target_vendor = "apple"))]
+use libc::dirent64;
+use libc::{c_char, c_int, c_void, dirent, dlsym, DIR, RTLD_NEXT};
 use log::{error, info};
 use once_cell::sync::OnceCell;
 use rand::seq::SliceRandom;