The first error I see in the log is:
:info:build ../../gcc-4.8-20121118/gcc/tree-data-ref.c:1599:19: error: second argument to 'va_arg' is of non-POD type 'affine_fn' (aka 'vec<tree>') [-Wnon-pod-varargs]
:info:build ret->fns[i] = va_arg (ap, affine_fn);
:info:build ^~~~~~~~~~~~~~~~~~~~~~
:info:build /usr/bin/../lib/clang/3.0/include/stdarg.h:35:50: note: instantiated from:
:info:build #define va_arg(ap, type) __builtin_va_arg(ap, type)
:info:build ^
:info:build ../../gcc-4.8-20121118/gcc/tree-data-ref.c:1599:31: note: instantiated from:
:info:build ret->fns[i] = va_arg (ap, affine_fn);
:info:build ^~~~~~~~~
I also see you're on Lion, and the above shows the use of files related to clang 3.0. The version of clang in the latest version of the Xcode command line tools is 4.1, so try updating Xcode to 4.5.2, then upgrading the Xcode command line tools (open Xcode.app -> Preferences -> Downloads).
