am 5dce6d19: am 5b81b918: libc: optimize memmove() with memcpy() if possible.

Merge commit '5dce6d195ac2c44614351f349e00ff5d8ebbe0bf'

* commit '5dce6d195ac2c44614351f349e00ff5d8ebbe0bf':
  libc: optimize memmove() with memcpy() if possible.