Building GHC 6.12 with GHC 6.12 + alex

Folks, I've run into trouble building GHC 6.12 with alex built from GHC 6.12: "/Users/alatter/usr/bin/alex" -g compiler/parser/Lexer.x -o compiler/stage1/build/Lexer.hs alex: compiler/parser/Lexer.x: hGetContents: invalid argument (Illegal byte sequence) however things like: ghci> readFile "compiler/parser/Lexer.x" apear to work just fine. Has anyone else seen this? Has anyone else succeeded in this? This is on Mac OS X 10.6, running on Intel Core 2 Duo. I'm trying to compile a recent pull of the 6.12 branch. Thanks, Antoine