The testing scheme for vhd2vl is sensitive to subtle shifts in
iverilog's parenthesization choices, meaning that the golden test
outputs require constant maintenance.
The patch previously applied in order to deal with this situation is
no longer sufficient, so a patch which is sufficient has been added.
Also, the `buildTargets` and `checkTarget` attributes have been set,
so future benign failures of this sort can be dealt with through
`doCheck=false` in a pinch.
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