Hi, As I wrote in the following blog article, I could build GHC head on Mavericks 20 days ago. http://d.hatena.ne.jp/kazu-yamamoto/20131028/1382921924 But I cannot build it recently: ---- "/usr/bin/ghc" -hisuf hi -osuf o -hcsuf hc -static -H32m -O -package-db libraries/bootstrapping.conf -i -iutils/genprimopcode/. -iutils/genprimopcode/dist/build -iutils/genprimopcode/dist/build/autogen -Iutils/genprimopcode/dist/build -Iutils/genprimopcode/dist/build/autogen -package array -no-user-package-db -rtsopts -odir utils/genprimopcode/dist/build -hidir utils/genprimopcode/dist/build -stubdir utils/genprimopcode/dist/build -c utils/genprimopcode/dist/build/Lexer.hs -o utils/genprimopcode/dist/build/Lexer.o <built-in>:2:2: Not in scope: `#' make[1]: *** [utils/genprimopcode/dist/build/Lexer.o] Error 1 make[1]: *** Waiting for unfinished jobs.... shift/reduce conflicts: 46 reduce/reduce conflicts: 1 make: *** [all] Error 2 ---- I seems to me that linemarkers generated by GCC(CPP) is not correctly handled when alex is used. Note I can build GHC head on FreeBSD and Linux. I'm using clang with clang-xcode5-wrapper.hs. Any suggestions? --Kazu