building head fails with: ghci/DebuggerTys.hs:49:60: Not in scope: `unknownTyConName'

[Claus Reinke]

../compiler/stage1/ghc-inplace -H32m -O2  -istage2/utils  -istage2/basicTypes  -istage2/types  -istage2/hsSyn 
  -istage2/prelude  -istage2/rename  -istage2/typecheck  -istage2/deSugar  -istage2/coreSyn  -istage2/specialise 
  -istage2/simplCore  -istage2/stranal  -istage2/stgSyn  -istage2/simplStg  -istage2/codeGen  -istage2/main 
  -istage2/profiling  -istage2/parser  -istage2/cprAnalysis  -istage2/ndpFlatten  -istage2/iface  -istage2/cmm 
  -istage2/nativeGen  -istage2/ghci -Istage2 -DGHCI -package 
template-haskell -DGHCI_TABLES_NEXT_TO_CODE -threaded -cpp -fglasgow-exts -fno-generics -Rghc-timing 
 -I. -Iparser -package Win32 -package Cabal -ignore-package lang -recomp -Rghc-timing  -H16M 
'-#include "cutils.h"' -package-name  ghc-6.7.20070501   -fgenerics    -c ghci/DebuggerTys.hs -o 
stage2/ghci/DebuggerTys.o  -ohi stage2/ghci/DebuggerTys.hi


ghci/DebuggerTys.hs:49:60: Not in scope: `unknownTyConName'



ghci/DebuggerTys.hs:53:60: Not in scope: `unknown1TyConName'



ghci/DebuggerTys.hs:56:60: Not in scope: `unknown2TyConName'



ghci/DebuggerTys.hs:59:60: Not in scope: `unknown3TyConName'

<<ghc: 38390604 bytes, 9 GCs, 1673698/3234100 avg/max bytes residency (2 samples), 17M in use, 0.01 
INIT (0.00 elapsed), 0.08 MUT (0.11 elapsed), 0.09 GC (0.09 elapsed) :ghc>>

make[2]: *** [stage2/ghci/DebuggerTys.o] Error 1
make[2]: Leaving directory `/cygdrive/c/fptools/ghc2/compiler'
make[1]: *** [stage2] Error 2
make[1]: Leaving directory `/cygdrive/c/fptools/ghc2'
make: *** [bootstrap2] Error 2