build problems with BuildFlavour = prof

I would like to use install the transformers library onto HEAD. I tried the following steps:

- Fresh checkout of HEAD
- BuildFlavour = quick
- perl boot; configure; make
- make install
- cabal install transformers

Cabal errors in looking for Data.Traversable, suggesting that I need the profiling version of the base library. OK. So I did the following:

- Another fresh checkout of HEAD
- BuildFlavour = prof
- perl boot; configure; make

Now, I get a failure:

make[1]: *** No rule to make target `libraries/base/dist-install/build/Prelude.dyn_p_hi', needed by `ghc/starge2/build/Main.dyn_o'.  Stop.

This leads to two questions:

1) Is cabal's error correct? Do I really need to enable profiling to get transformers working? Or is some other incompatibility at play here? (For what it's worth, what I really want is the mtl library, but that depends on transformers.)
2) Is there a bug in the build process for BuildFlavour = prof?

If it matters, I am using GHC 7.6.1 as my base compiler on Mac OS 10.7.5. I can give other version numbers, etc., on request.

Thanks!
Richard