http://gcc.gnu.org/bugzilla/show_bug.cgi?id=49919
--- Comment #9 from Jack Howarth <howarth at nitro dot med.uc.edu> 2011-07-31 17:38:00 UTC --- (In reply to comment #8) Those instructions predate Lion which now defaults gcc/cc to llvm-gcc-4.2/llvm-g++-4.2 instead of gcc-4.2/g++-4.2. Again http://llvm.org/bugs/show_bug.cgi?id=9571 is unfixed in Xcode 4.1 which is the origin of the bootstrap failures. Use CC=gcc-4.2 CXX=g++-4.2 or CC=clang CXX=clang++ when bootstrapping FSF gcc under Lion.
