(potentially) MD versions (function dependent, not filename dependent)
split out memcpy/memmove/bcopy and strchr/index/strrchr/rindex
Bring back amd64 .S versions
And the final touch: switch all architectures temporarily to MI
memcpy.c, which contains syslog + abort for overlapping copies.  A nice
harsh undefined behaviour.  We will clean the entire userland of the
remaining issues in this catagory, then switch to the optimised memcpy
which skips the memmove check.
I tried to cut this change into pieces, but testing each sub-step on
every architecture is too time consuming and mindnumbing.
ok miod