OSX Lion building 7.4 head causes Haddock Divide By Zero

After installing 7.2.2 64 bit onto a GHC-free system, I tried to build the full 7.4 head from git repositories according to the wiki instructions. The result was:

haddock: internal error: divide by zero
make[1]: *** [libraries/base/dist-install/doc/html/base/base.haddock] Error 1
make: *** [all] Error 2

This halted the build.

More detail follows -- a little bit more output, followed by reproduction steps.

Haddock coverage:
  50% (  1 /  2) in 'Unsafe.Coerce'
   0% (  0 /  1) in 'GHC.IO.Encoding.CodePage'
Warning: base:GHC.Base: Could not find documentation for exported module: GHC.Err
  65% ( 30 / 46) in 'GHC.Base'
  67% (  4 /  6) in 'GHC.Num'
 100% (  6 /  6) in 'Data.Tuple'
 100% ( 11 / 11) in 'Data.Maybe'
  89% ( 42 / 47) in 'GHC.List'
  65% ( 11 / 17) in 'GHC.Show'
  33% (  3 /  9) in 'GHC.Enum'
  25% (  2 /  8) in 'Text.Show'
  95% ( 41 / 43) in 'Control.Monad'
  50% (  5 / 10) in 'GHC.ST'
  34% ( 17 / 50) in 'GHC.Arr'
 100% (  6 /  6) in 'GHC.Exception'
  50% (  3 /  6) in 'GHC.Err'
  50% ( 16 / 32) in 'GHC.Real'
  59% ( 19 / 32) in 'GHC.IO'
  88% (  7 /  8) in 'GHC.IOArray'
 100% (  3 /  3) in 'Foreign.Marshal.Unsafe'
 100% ( 11 / 11) in 'GHC.MVar'
 100% (  2 /  2) in 'Data.Bits'
  29% (  9 / 31) in 'GHC.Float.RealFracMethods'
  33% (  1 /  3) in 'GHC.Float.ConversionUtils'
haddock: internal error: divide by zero
make[1]: *** [libraries/base/dist-install/doc/html/base/base.haddock] Error 1
make: *** [all] Error 2

Reproduction Steps:

Xcode 4.2.1 Build version 4D502

Mac OSX Lion 10.7.2 (11C74) (from About This Mac)

hardware:

Model Name:	MacBook Pro
  Model Identifier:	MacBookPro8,2
  Processor Name:	Intel Core i7
  Processor Speed:	2.3 GHz
  Number of Processors:	1
  Total Number of Cores:	4
  L2 Cache (per Core):	256 KB
  L3 Cache:	8 MB
  Memory:	8 GB
  Boot ROM Version:	MBP81.0047.B24
  SMC Version (system):	1.69f3

Step 1:

Install on a clean system the installer based package from

http://www.haskell.org/ghc/download_ghc_7_2_2#macosx_x86_64

Step 2: Acquiring the 7.4 source:

(according to http://hackage.haskell.org/trac/ghc/wiki/Building/GettingTheSources)

mkdir ghc-builds
cd ghc-builds
git clone -b ghc-7.4 http://darcs.haskell.org/ghc.git/ ghc-7.4
cd ghc-7.4
./sync-all --testsuite get -b ghc-7.4
./sync-all pull

Step 3: Backed up ghc-7.4 to archive .rar file for wipe-and-rebuild

Step 4: Configuration and make

(according to http://hackage.haskell.org/trac/ghc/wiki/Building/Hacking)

perl boot
./configure --prefix=/Users/michaeljones/ghc-builds/ghc-7.4-install
make