I'd like to build pugs on OS X and so I've installed ghc 6.6.1 and the extras from source. Anyway making pugs ends on this point:

[17 of 92] Compiling Pugs.Internals   ( src/Pugs/Internals.hs, dist/bu
+ild/Pugs/Internals.o )

src/Pugs/Internals.hs:124:26:
    Module `Control.Monad.RWS' does not export `MonadIO(..)'

src/Pugs/Internals.hs:124:89:
    Module `Control.Monad.RWS' does not export `MonadTrans(..)'

src/Pugs/Internals.hs:124:111:
    Module `Control.Monad.RWS' does not export `ReaderT(..)'

src/Pugs/Internals.hs:124:124:
    Module `Control.Monad.RWS' does not export `WriterT(..)'

src/Pugs/Internals.hs:124:137:
    Module `Control.Monad.RWS' does not export `when'

src/Pugs/Internals.hs:124:143:
    Module `Control.Monad.RWS' does not export `join'

src/Pugs/Internals.hs:124:149:
    Module `Control.Monad.RWS' does not export `liftM'

src/Pugs/Internals.hs:124:156:
    Module `Control.Monad.RWS' does not export `filterM'

src/Pugs/Internals.hs:124:173:
    Module `Control.Monad.RWS' does not export `unless'

src/Pugs/Internals.hs:124:187:
    Module `Control.Monad.RWS' does not export `foldM'

src/Pugs/Internals.hs:124:194:
    Module `Control.Monad.RWS' does not export `guard'

src/Pugs/Internals.hs:124:201:
    Module `Control.Monad.RWS' does not export `liftM2'

src/Pugs/Internals.hs:124:209:
    Module `Control.Monad.RWS' does not export `liftM3'

src/Pugs/Internals.hs:124:217:
    Module `Control.Monad.RWS' does not export `fix'

src/Pugs/Internals.hs:124:222:
    Module `Control.Monad.RWS' does not export `mplus'

src/Pugs/Internals.hs:124:229:
    Module `Control.Monad.RWS' does not export `mappend'

src/Pugs/Internals.hs:124:238:
    Module `Control.Monad.RWS' does not export `mzero'

src/Pugs/Internals.hs:124:245:
    Module `Control.Monad.RWS' does not export `mconcat'

src/Pugs/Internals.hs:124:254:
    Module `Control.Monad.RWS' does not export `msum'
Build failed: 256 at util/build_pugs.pl line 360.
make: *** [pugs] Error 2
  AUDREYT/Perl6-Pugs-6.2.13.tar.gz
  /usr/bin/make -- NOT OK
Failed during this command:
 AUDREYT/Perl6-Pugs-6.2.13.tar.gz             : make NO
[download]

Anyone an idea how to proceed?