Resolve a ctest FIXME regarding use of size_of in array lengths

Author: tgross35

src/unix/linux_like/linux/musl/mod.rs

@@ -422,11 +422,7 @@ s_no_extra_traits! {
         pub aio_offset: off_t,
         __next: *mut c_void,
         __prev: *mut c_void,
-        // FIXME(ctest): length should be `32 - 2 * size_of::<*const ()>()`
-        #[cfg(target_pointer_width = "32")]
-        __dummy4: [c_char; 24],
-        #[cfg(target_pointer_width = "64")]
-        __dummy4: [c_char; 16],
+        __dummy4: [c_char; 32 - 2 * size_of::<*const ()>()],
     }
 
     pub struct sysinfo {