Add to 'config'.

from Weny Palm

BIO_nwrite0/BIO_nwrite (the previous code was OK for BIO pairs but not
in general)

  [Chosen plaintext attack: R. Merkle, M. Hellman: "On the Security of
  Multiple Encryption", CACM 24 (1981) pp. 465-467, p. 776.

  Known plaintext angriff: P.C. van Oorschot, M. Wiener: "A
  known-plaintext attack on two-key triple encryption", EUROCRYPT '90.]

main branches)

Submitted by:  Oscar Jacobsson <oscar@jacobsson.org>

need for e_os.h.

This is especially important for AES that has a 16 bytes IV.

it's exported.  Changing that is a BIG step, which has been done in
0.9.7-dev.

Submitted by Ian Marsh <mushypea@dominion.net.uk>

'OpenSSL_0_9_6-stable'.