[make whiz handle Let's better
John Meacham <john@repetae.net>**20060815031341] hunk ./Grin/Whiz.hs 85
+    g env lt@Let { expDefs = defs, expBody = Let { expDefs = defs', expBody = body } } = g env lt { expDefs = defs `mappend` defs', expBody = body }