OpenSSL: Use SSL_MODE_RELEASE_BUFFERS if available, reduces memory use

See also :
http://www.openssl.org/docs/ssl/SSL_CTX_set_mode.html
http://www.imperialviolet.org/2010/06/25/overclocking-ssl.html



Signed-off-by: Cristian Rodríguez <crrodriguez@opensuse.org>

TODO-RELEASE

@@ -43,9 +43,6 @@ To be addressed in 7.21.8 (or 7.22.0?)
       http://curl.haxx.se/mail/lib-2011-07/0186.html and
       http://curl.haxx.se/mail/lib-2011-08/0008.html
 
-305 - "Use SSL_MODE_RELEASE_BUFFERS if available," by Cristian Rodrguez
-      http://curl.haxx.se/mail/lib-2011-08/0017.html
-
 306 - SSL Sessions shared by Alejandro Alvarez Ayllon
       http://curl.haxx.se/mail/lib-2011-08/0002.html
 

lib/ssluse.c

@@ -1489,6 +1489,10 @@ ossl_connect_step1(struct connectdata *conn,
     return CURLE_OUT_OF_MEMORY;
   }
 
+#ifdef SSL_MODE_RELEASE_BUFFERS
+  SSL_CTX_set_mode(connssl->ctx, SSL_MODE_RELEASE_BUFFERS);
+#endif
+
 #ifdef SSL_CTRL_SET_MSG_CALLBACK
   if(data->set.fdebug && data->set.verbose) {
     /* the SSL trace callback is only used for verbose logging so we only