Glibc change exposing bugs

Having seen all sorts of crazy memcpies using MMX (glibc, DirectFB, kernel, etc, etc) and having tried to benchmark them, observing huge amounts of noise in the experinemtns, I have come to the conclusion that the best memcpy one can use is gcc's __builtin_memcpy.

There is also a big advantage by doing that: hopefully gcc in some cases can detect the alignment of pointers at compile-time and use even faster variants, which is even more important.

At least we hope that the gcc devs will remain sane (inclusion of "go" frontend is scary knowing that google tends to withdraw services and software without much thought (wave, etc))...