compiling hat with ghc 6.4 on debian

$ make
...
MkProg: hmake: the compiler 'ghc' is not known.

Stop - hmake dependency error.
$ locate hmakerc
/var/lib/hmake/debian/hmakerc
$ hmake-config `locate hmakerc` list
Global config file is:
    /var/lib/hmake/debian/hmakerc
Known compilers:
    ghc6        (6.4)
    /usr/bin/haskell-compiler   (6.4)
    /usr/bin/ghc6       (6.4)
Default compiler:
    /usr/bin/haskell-compiler
$ hmake-config new
hmake-config: Starting new personal config file in
.../.hmakerc/debian
$ hmake-config add ghc