add MOVE_ARRAY
Similar to COPY_ARRAY (introduced in
60566cbb58), add a safe and
convenient helper for moving potentially overlapping ranges of array
entries. It infers the element size, multiplies automatically and
safely to get the size in bytes, does a basic type safety check by
comparing element sizes and unlike memmove(3) it supports NULL
pointers iff 0 elements are to be moved.
Also add a semantic patch to demonstrate the helper's intended usage.
Signed-off-by: Rene Scharfe <l.s.r@web.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>