The build fails with a segfault when building HEAD using GHC 7.2, OS X 10.7, and XCode 4.1

Any ideas?

tibbe@redwood:ghc (master)$ make

===--- building phase 0

make -r --no-print-directory -f ghc.mk phase=0 phase_0_builds

make[1]: Nothing to be done for `phase_0_builds'.

===--- building phase 1

make -r --no-print-directory -f ghc.mk phase=1 phase_1_builds

make[1]: Nothing to be done for `phase_1_builds'.

===--- building final phase

make -r --no-print-directory -f ghc.mk phase=final all

"inplace/bin/ghc-stage1"   -H64m -O -fasm    -package-name ghc-prim-0.2.0.0 -hide-all-packages -i -ilibraries/ghc-prim/. -ilibraries/ghc-prim/dist-install/build -ilibraries/ghc-prim/dist-install/build/autogen -Ilibraries/ghc-prim/dist-install/build -Ilibraries/ghc-prim/dist-install/build/autogen -Ilibraries/ghc-prim/.    -optP-include -optPlibraries/ghc-prim/dist-install/build/autogen/cabal_macros.h -package rts-1.0  -package-name ghc-prim -XHaskell98 -XCPP -XMagicHash -XForeignFunctionInterface -XUnliftedFFITypes -XUnboxedTuples -XEmptyDataDecls -XNoImplicitPrelude -O -dcore-lint -no-user-package-conf -rtsopts     -odir libraries/ghc-prim/dist-install/build -hidir libraries/ghc-prim/dist-install/build -stubdir libraries/ghc-prim/dist-install/build -hisuf hi -osuf  o -hcsuf hc -c libraries/ghc-prim/./GHC/Debug.hs -o libraries/ghc-prim/dist-install/build/GHC/Debug.o

make[1]: *** [libraries/ghc-prim/dist-install/build/GHC/Debug.o] Segmentation fault: 11

make: *** [all] Error 2