[allow C generator to handle unknown values properly
John Meacham <john@repetae.net>**20090905070241
 Ignore-this: 45b178166521d1415a83296a417637ad
] hunk ./src/Grin/SSimplify.hs 177
+    f (Return [v@ValUnknown {}]) ((senv,[Var vn _],b):rs) = do
+        mtick "Grin.Simplify.Subst.unknown"
+        fbind vn v senv b rs