Support for fixed DH ciphersuites.

The cipher definitions of these ciphersuites have been around since SSLeay
but were always disabled. Now OpenSSL supports DH certificates they can be
finally enabled.

Various additional changes were needed to make them work properly: many
unused fixed DH sections of code were untested.

ssl/ssl_lib.c

@@ -2110,6 +2110,9 @@ void ssl_set_cert_masks(CERT *c, const SSL_CIPHER *cipher)
 	if (dh_dsa) mask_k|=SSL_kDHd;
 	if (dh_dsa_export) emask_k|=SSL_kDHd;
 
+	if (emask_k & (SSL_kDHr|SSL_kDHd))
+		mask_a |= SSL_aDH;
+
 	if (rsa_enc || rsa_sign)
 		{
 		mask_a|=SSL_aRSA;