Obtain the Name that corresponds to a top-level (Prelude-level) Haskell identifier. Given an expression such as [e| (+) |] we return the expression that is the application of mkNameG_v to the correct strings. That expression, when spliced in, will compute exactly the same name that corresponds to the one we started with, that is, (+). Note that (+) was the identifier, not the name. The result of splicing reifyName can be used in splices (see the Diff.hs for examples). We essentially apply the TH to itself and emulate more than one stage of computation.