Add system variable stubs

SMILEBASIC/compiler.d

@@ -258,6 +258,11 @@ class Compiler
         addSystemVariable("MILLISEC", new MilliSecond());
         addSystemVariable("PRGSLOT", new ProgramSlot());
         addSystemVariable("CALLIDX", new CallIndex());
+        addSystemVariable("MPCOUNT", new Zero());
+        addSystemVariable("MPHOST", new Zero());
+        addSystemVariable("MPLOCAL", new Zero());
+        addSystemVariable("MICPOS", new Zero());
+        addSystemVariable("MICSIIZE", new Zero());
     }
     void addSystemVariable(wstring name, SystemVariable var)
     {

SMILEBASIC/systemvariable.d

@@ -149,3 +149,11 @@ class CallIndex : SystemVariable
         return Value(vm.petitcomputer.callidx);
     }
 }
+class Zero : SystemVariable
+{
+    @property override Value value()
+    {
+        return Value(0);
+    }
+}
+