building ghc-7.1.20110125 under Mac OS X

hi list. i have to build ghc-7.1.20110125 under mac os x, so i grabbed the stable snapshot. Everything builds fine but the resulting compiler has problems with ld. It passes gcc flags to ld like "-march=-i686". Any ideas? BTW while still here. Are there any specific docs available on building 64-bit mac os x compiler? regards pavel