$OpenBSD$

Fix error from clang:
gui/simwin.cc:498:11: error: case value evaluates to -1, which cannot be
      narrowed to type 'uint32' (aka 'unsigned int') [-Wc++11-narrowing]
                                        case magic_none: return;
                                             ^

Index: gui/simwin.cc
--- gui/simwin.cc.orig
+++ gui/simwin.cc
@@ -492,7 +492,7 @@ void rdwr_all_win(loadsave_t *file)
 				file->rdwr_long(id);
 				// create the matching
 				gui_frame_t *w = NULL;
-				switch(id) {
+				switch(magic_numbers(id)) {
 
 					// end of dialogues
 					case magic_none: return;
