Merge branch '2.4.x'

* 2.4.x:
  Release 2.4.3.
  debian/control: Don't require `valgrind' on `armel'.
  progs/perftest.c: Document the `-n' option for `enc' and `hash'.
  key/key-misc.c: Fix bogus parentheses in macro.
  symm/rijndael-arm64-crypto.S: Fix bogus element-to-GP move.
  symm/chacha.c: Set the correct nonce size for `xchachaNN'.
  symm/idea.c: Fix key-size descriptor.