Revise network definitions for HorizonOS

(backport <rust-lang#3863>)
(cherry picked from commit 82ebf14)

src/unix/newlib/horizon/mod.rs

@@ -21,6 +21,14 @@ pub type sbintime_t = ::c_longlong;
 pub type sigset_t = ::c_ulong;
 
 s! {
+    pub struct hostent {
+        pub h_name: *mut ::c_char,
+        pub h_aliases: *mut *mut ::c_char,
+        pub h_addrtype: u16,
+        pub h_length: u16,
+        pub h_addr_list: *mut *mut ::c_char,
+    }
+
     pub struct sockaddr {
         pub sa_family: ::sa_family_t,
         pub sa_data: [::c_char; 26usize],
@@ -35,6 +43,7 @@ s! {
         pub sin_family: ::sa_family_t,
         pub sin_port: ::in_port_t,
         pub sin_addr: ::in_addr,
+        pub sin_zero: [::c_char; 8],
     }
 
     pub struct sockaddr_in6 {

src/unix/newlib/mod.rs

@@ -53,6 +53,21 @@ cfg_if! {
     }
 }
 
+cfg_if! {
+    if #[cfg(not(target_os = "horizon"))] {
+        s!{
+            pub struct hostent {
+                pub h_name: *mut ::c_char,
+                pub h_aliases: *mut *mut ::c_char,
+                pub h_addrtype: ::c_int,
+                pub h_length: ::c_int,
+                pub h_addr_list: *mut *mut ::c_char,
+                pub h_addr: *mut ::c_char,
+            }
+        }
+    }
+}
+
 s! {
     // The order of the `ai_addr` field in this struct is crucial
     // for converting between the Rust and C types.
@@ -87,16 +102,7 @@ s! {
     }
 
     pub struct in_addr {
-            pub s_addr: ::in_addr_t,
-    }
-
-    pub struct hostent {
-            pub h_name: *mut ::c_char,
-            pub h_aliases: *mut *mut ::c_char,
-            pub h_addrtype: ::c_int,
-            pub h_length: ::c_int,
-            pub h_addr_list: *mut *mut ::c_char,
-            pub h_addr: *mut ::c_char,
+        pub s_addr: ::in_addr_t,
     }
 
     pub struct pollfd {