Fix bug that could cause generation of invalid sym files.

When these invalid sym files were used during subsequent compiles, certain type pointers (for what should be const-qualified struct or union types) could be left uninitialized, or possibly initialized pointing to different types. This could result in spurious errors or potentially in other problems.

Parser.pas

@@ -3030,6 +3030,7 @@ if isconstant then begin                {handle a constant type}
          size := typeSpec^.size;
          kind := definedType;
          dType := typeSpec;
+         saveDisp := 0;
          end; {with}
       end {if}
    else