Add sockaddr_vm definition for Fuchsia

Author: jamesr

src/fuchsia/mod.rs

@@ -357,6 +357,14 @@ s! {
         pub sin6_scope_id: u32,
     }
 
+    pub struct sockaddr_vm {
+        pub svm_family: sa_family_t,
+        pub svm_reserved: u16,
+        pub svm_port: crate::in_port_t,
+        pub svm_cid: u32,
+        pub svm_zero: [u8; 4],
+    }
+
     pub struct addrinfo {
         pub ai_flags: c_int,
         pub ai_family: c_int,