RT 1988: Add "const" to SSL_use_RSAPrivateKey_ASN1

The "unsigned char *d" should be const.
Reviewed-by: Kurt Roeckx <kurt@roeckx.be>
Undo a90081576c94f9f54de1755188a00ccc1760549a

Undo unapproved commit that removed DJGPP and WATT32
Test SRP authentication ciphersuites.

Reviewed-by: Matt Caswell <matt@openssl.org>
Fix SRP authentication ciphersuites.

The addition of SRP authentication needs to be checked in various places
to work properly. Specifically:

A certificate is not sent.
A certificate request must not be sent.
Server key exchange message must not contain a signature.
If appropriate SRP authentication ciphersuites should be chosen.
Reviewed-by: Matt Caswell <matt@openssl.org>