Help!  I can’t build ghc!

I get this

utils/ghc-pkg/Main.hs:1160:24:

    Not in scope: `showSimpleInstalledPackageInfoField'

    Perhaps you meant `showInstalledPackageInfoField' (imported from Distribution.InstalledPackageInfo)

And indeed, my libraries/Cabal is way behind

simonpj@cam-05-unx:~/code/HEAD$ cd libraries/Cabal

simonpj@cam-05-unx:~/code/HEAD/libraries/Cabal$ git log -1

commit 14c5a3f78c00772cf54c2fd5c920a64d53e6f594

Author: Gabor Greif <ggreif@gmail.com>

Date:   Wed Mar 20 22:27:15 2013 +0100

            Fix typos

“git submodule status” says

14c5a3f78c00772cf54c2fd5c920a64d53e6f594 libraries/Cabal (1_10_branch_forked-1682-g14c5a3f)

1f9f7175e747aad7c424f5b12be5b95f15286f0b libraries/Win32 (2009-06-25-50-g1f9f717)

...etc

In another tree entirely “git submodule status” says

  b4d0c0... libraries/Cabal

which looks right, because that commit does futz with showInstalledPackageInfoField.

So it looks as if my main GHC repo somehow has the wrong commit for Cabal.  How do I make it right? 

This is so frustrating.  Thanks

Simon