While trying to build head (from a maintainer-clean tree) I get the following error: echo "compiler_stage1_depfile_haskell_EXISTS = YES" >> compiler/stage1/build/.depend-v.haskell.tmp for dir in compiler/stage1/build/./ compiler/stage1/build/Llvm/ compiler/stage1/build/LlvmCodeGen/ compiler/stage1/build/PPC/ compiler/stage1/build/RegAlloc/ compiler/stage1/build/RegAlloc/Graph/ compiler/stage1/build/RegAlloc/Linear/ compiler/stage1/build/RegAlloc/Linear/PPC/ compiler/stage1/build/RegAlloc/Linear/SPARC/ compiler/stage1/build/RegAlloc/Linear/X86/ compiler/stage1/build/SPARC/ compiler/stage1/build/SPARC/CodeGen/ compiler/stage1/build/Vectorise/ compiler/stage1/build/Vectorise/Builtins/ compiler/stage1/build/Vectorise/Monad/ compiler/stage1/build/Vectorise/Type/ compiler/stage1/build/Vectorise/Utils/ compiler/stage1/build/X86/; do if test ! -d $dir; then mkdir -p $dir; fi done grep -v ' : [a-zA-Z]:/' compiler/stage1/build/.depend-v.haskell.tmp > compiler/stage1/build/.depend-v.haskell "/usr/sbin/dtrace" -Iincludes -Irts -Ilibffi/build/include -C -x cpppath=/usr/bin/gcc -h -o rts/dist/build/RtsProbes.h -s rts/RtsProbes.d . includes/HsFFI.h .. includes/ghcconfig.h ... includes/ghcautoconf.h ... includes/ghcplatform.h .. includes/stg/Types.h .. /usr/lib/gcc/i686-apple-darwin10/4.2.1/include/stdint.h .. /usr/lib/gcc/i686-apple-darwin10/4.2.1/include/float.h . includes/rts/EventLogFormat.h dtrace: failed to compile script rts/RtsProbes.d: line 71: parameter is already declared in probe input prototype: StgWord, parameter #6 make[1]: *** [rts/dist/build/RtsProbes.h] Error 1 make: *** [all] Error 2