Make serial fd blocking mode depend on FILE_FLAG_OVERLAPPED.

diff --git a/server/trace.c b/server/trace.c
index eeb323c..9ce6400 100644
--- a/server/trace.c
+++ b/server/trace.c
@@ -1556,6 +1556,7 @@
 {
     fprintf( stderr, " access=%08x,", req->access );
     fprintf( stderr, " inherit=%d,", req->inherit );
+    fprintf( stderr, " attributes=%08x,", req->attributes );
     fprintf( stderr, " sharing=%08x,", req->sharing );
     fprintf( stderr, " name=" );
     cur_pos += dump_varargs_string( req );