deriveConstants: Fix nm-classic error message
deriveConstants: Fix nm-classic error message

Thanks to George Colpitts for the suggestion.

(cherry picked from commit 28503fe984dbc00f687f0579967d583eebb9afcb)

GaloisInc/halvm-ghc,GaloisInc/halvm-ghc,GaloisInc/halvm-ghc,GaloisInc/halvm-ghc,GaloisInc/halvm-ghc,GaloisInc/halvm-ghc,GaloisInc/halvm-ghc