GHC HEAD build error

Hello, I'm trying to build GHC HEAD but get the following error: "inplace/bin/ghc-stage1" -H64m -O0 -fasm -Iincludes -Irts -Irts/dist/build -DCOMPILING_RTS -package-name rts -dcmm-lint -i -irts -irts/dist/build -irts/dist/build/autogen -Irts/dist/build -Irts/dist/build/autogen -optc-O2 -c rts/HeapStackCheck.cmm -o rts/dist/build/HeapStackCheck.o rts/HeapStackCheck.cmm:159:305: parse error on input `(' The bug is in the GC_GENERIC macro on line 99: Capability_interrupt(MyCapability()) != 0 :: CInt However, I can't spot the problem. Bas