Pass "-i org.haskell.GHC" to packagemaker when building the OS X installer

Pass "-i org.haskell.GHC" to packagemaker when building the OS X installer
This seems to fix this failure:
[...]
** BUILD SUCCEEDED **
rm -f -f GHC-system.pmdoc/*-contents.xml
/Developer/usr/bin/packagemaker -v --doc GHC-system.pmdoc\
             -o /Users/ian/to_release/ghc-6.12.1.20100330/GHC-6.12.1.20100330-i386.pkg
2010-03-31 15:08:15.695 packagemaker[13909:807] Setting to : 0 (null)
2010-03-31 15:08:15.709 packagemaker[13909:807] Setting to : 0 org.haskell.glasgowHaskellCompiler.ghc.pkg
2010-03-31 15:08:15.739 packagemaker[13909:807] relocate: (null) 0
2010-03-31 15:08:15.740 packagemaker[13909:807] *** Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '*** -[NSXMLDocument initWithXMLString:options:error:]: nil argument'
2010-03-31 15:08:15.741 packagemaker[13909:807] Stack: (
    2511962091,
    2447007291,
    2511961547,
    2511961610,
    2432803204,
    453371,
    447720,
    436209,
    435510,
    9986,
    9918
)
make[1]: *** [framework-pkg] Trace/BPT trap
make: *** [framework-pkg] Error 2