Initial "opaque SSL" framework. If an application defines OPENSSL_NO_SSL_INTERN

all ssl related structures are opaque and internals cannot be directly
accessed. Many applications will need some modification to support this and
most likely some additional functions added to OpenSSL.

The advantage of this option is that any application supporting it will still
be binary compatible if SSL structures change.

(backport from HEAD).

ssl/ssl2.h

@@ -155,6 +155,8 @@ extern "C" {
 #define  CERT		char
 #endif
 
+#ifndef OPENSSL_NO_SSL_INTERN
+
 typedef struct ssl2_state_st
 	{
 	int three_byte_header;
@@ -219,6 +221,8 @@ typedef struct ssl2_state_st
 		} tmp;
 	} SSL2_STATE;
 
+#endif
+
 /* SSLv2 */
 /* client */
 #define SSL2_ST_SEND_CLIENT_HELLO_A		(0x10|SSL_ST_CONNECT)