Auto merge of #60547 - redox-os:redox-unix, r=alexcrichton

redox: convert to target_family unix

This is the second step to supporting #60139.

In order to have a smooth transition, there will need to be a change made in liblibc at the same time, switching Redox over to the unix target family. See rust-lang/libc#1332

Author: bors

src/doc/unstable-book/src/library-features/n16.md

@@ -48,8 +48,7 @@ pub unsafe extern fn __rust_start_panic(_payload: usize) -> u32 {
         libc::abort();
     }
 
-    #[cfg(any(target_os = "redox",
-              windows,
+    #[cfg(any(windows,
               all(target_arch = "wasm32", not(target_os = "emscripten"))))]
     unsafe fn abort() -> ! {
         core::intrinsics::abort();