port from vanilla: initialize save-as name of untitled patches so that if you

just leave the title unchanged you don't get "save as" action again on
next save

commit: 470032130e2b0135b97151d719c4706d68f3c380

We ignore the reversion and workaround in a later vanilla commit for an
OSX tk issue that doesn't apply to nw.js

pd/src/g_readwrite.c

@@ -885,7 +885,12 @@ static void canvas_savetofile(t_canvas *x, t_symbol *filename, t_symbol *dir,
 static void canvas_menusaveas(t_canvas *x, t_floatarg fdestroy)
 {
     t_canvas *x2 = canvas_getrootfor(x);
-    gui_vmess("gui_canvas_saveas", "xssi", x2, x2->gl_name->s_name, canvas_getdir(x2)->s_name, fdestroy != 0);
+    gui_vmess("gui_canvas_saveas", "xssi",
+        x2,
+        (strncmp(x2->gl_name->s_name, "Untitled", 8) ?
+            x2->gl_name->s_name : "title"),
+        canvas_getdir(x2)->s_name,
+        fdestroy != 0);
 }
 
 static void canvas_menusave(t_canvas *x, t_floatarg fdestroy)