diff --git a/ext/socket/ancdata.c b/ext/socket/ancdata.c
index 5af090c9b9..9344252864 100644
--- a/ext/socket/ancdata.c
+++ b/ext/socket/ancdata.c
@@ -1114,7 +1114,7 @@ static void *
 nogvl_sendmsg_func(void *ptr)
 {
     struct sendmsg_args_struct *args = ptr;
-    return (void *)sendmsg(args->fd, args->msg, args->flags);
+    return (void *)(VALUE)sendmsg(args->fd, args->msg, args->flags);
 }
 
 static ssize_t
diff --git a/ext/socket/option.c b/ext/socket/option.c
index 1f334bbca0..4cef1c81c4 100644
--- a/ext/socket/option.c
+++ b/ext/socket/option.c
@@ -452,6 +452,8 @@ inet_ntop(int af, const void *addr, char *numaddr, size_t numaddr_len)
 #endif
     return numaddr;
 }
+#elif !defined HAVE_ARPA_INET_H
+extern char *inet_ntop(int af, const void *addr, char *numaddr, size_t numaddr_len);
 #endif
 
 /* Although the buffer size needed depends on the prefixes, "%u" may generate "4294967295".  */