struct addrinfo needs padding on Solaris/SPARC

64-bit Solaris/SPARC has a 4-byte pad before ai_addrlen for historical
reasons (ai_addrlen used to be defined as a size_t, which is 4 bytes in
ILP32 and 8 in LP64, but was converted to a 4-byte socklen_t in Solaris
10, which necessitated padding for (more or less) binary compatibility).

src/unix/solaris/mod.rs

@@ -208,6 +208,8 @@ s! {
         pub ai_family: ::c_int,
         pub ai_socktype: ::c_int,
         pub ai_protocol: ::c_int,
+        #[cfg(target_arch = "sparc64")]
+        __sparcv9_pad: ::c_int,
         pub ai_addrlen: ::socklen_t,
         pub ai_canonname: *mut ::c_char,
         pub ai_addr: *mut ::sockaddr,