Implement CHKLABEL(label,global)

SMILEBASIC/VM.d

@@ -438,7 +438,7 @@ class VM
             return true;
         return false;
     }
-    bool chklabel(wstring label)
+    bool chklabel(wstring label, bool global)
     {
         auto name = parse(label);
         VMSlot slot;
@@ -454,10 +454,15 @@ class VM
         {
             slot = currentSlot;
         }
+        if (currentFunction)
+        {
+            if (name.name in currentFunction.label)
+                return true;
+            if (!global)
+                return false;
+        }
         if (name.name in slot.globalLabel)
             return true;
-        if (currentFunction && name.name in currentFunction.label)
-            return true;
         return false;
     }
     bool chkvar(wstring var)