Revert "Simplify configuration of ai_addr"

This reverts commit 7ac91c6.

Author: raphlinus

src/unix/notbsd/mod.rs

@@ -54,13 +54,15 @@ s! {
         pub ai_addrlen: socklen_t,
 
         #[cfg(any(target_os = "linux",
-                  target_os = "android",
                   target_os = "emscripten",
                   target_os = "fuchsia"))]
         pub ai_addr: *mut ::sockaddr,
 
         pub ai_canonname: *mut c_char,
 
+        #[cfg(target_os = "android")]
+        pub ai_addr: *mut ::sockaddr,
+
         pub ai_next: *mut addrinfo,
     }