Haskell code generation results in unbuildable source for certain input DDL filenames

[jtdaugherty]

I used daedalus compile-hs on an input file called MDM-2.4.ddl. That succeeded in generating a parser source directory, but when I attempted to build it, I got this error:

Errors encountered when parsing cabal file hsout/hsout.cabal:

hsout/hsout.cabal:14:36: error:
unexpected '-'
expecting white space, ",", "\"" or end of input

   13 |   default-language:    Haskell2010
   14 |   other-modules:       Daedalus,MDM-2.4
      |                                    ^

It appears that input filenames containing dashes (or maybe even dots) might need to be normalized to underscore or something like that to avoid this problem.