Conditionally replace reinvention of memcpy() with calls to memcpy() gcc already knows how to inline memcpy calls with constant n, and also gets the alignment constraints right, avoiding incorrect unaligned accesses on armel.
Unconditionally define LZO_MEMOPS_GET_NE64 since it's trivial to do in terms of LZO_MEMOPS_COPY8.
I've made the "modern C" version conditional since lzo seems to aim to be portable to anything and everything, but it would probably be better off just requiring a compiler from this century and a set of correctly working memwhatever() implementations.
