osx,stream: retry sending handle on EMSGSIZE error

On OSX when sending handles via `sendmsg()` it can return `EMSGSIZE` if
there isn't room in the socket output buffer to store the whole message.
If that's the case, return control to the loop and try again in the next
iteration.

Fixes: nodejs/node#14828
PR-URL: libuv#1739
Reviewed-By: Colin Ihrig <[email protected]>

Author: santigimeno

src/unix/stream.c

@@ -58,6 +58,12 @@ struct uv__stream_select_s {
   fd_set* swrite;
   size_t swrite_sz;
 };
+# define WRITE_RETRY_ON_ERROR(send_handle) \
+    (errno == EAGAIN || errno == EWOULDBLOCK || errno == ENOBUFS || \
+     (errno == EMSGSIZE && send_handle))
+#else
+# define WRITE_RETRY_ON_ERROR(send_handle) \
+    (errno == EAGAIN || errno == EWOULDBLOCK || errno == ENOBUFS)
 #endif /* defined(__APPLE__) */
 
 static void uv__stream_connect(uv_stream_t*);
@@ -859,7 +865,7 @@ static void uv__write(uv_stream_t* stream) {
   }
 
   if (n < 0) {
-    if (errno != EAGAIN && errno != EWOULDBLOCK && errno != ENOBUFS) {
+    if (!WRITE_RETRY_ON_ERROR(req->send_handle)) {
       err = UV__ERR(errno);
       goto error;
     } else if (stream->flags & UV_STREAM_BLOCKING) {