- I did a cleanup of the internal generic SSL layer and how the various SSL

libraries are supported. Starting now, each underlying SSL library support
  code does a set of defines for the 16 functions the generic layer (sslgen.c)
  uses (all these new function defines use the prefix "curlssl_"). This
  greatly simplified the generic layer in readability by involving much less
  #ifdefs and other preprocessor stuff and should make it easier for people to
  make libcurl work with new SSL libraries.

  Hopefully I can later on document these 16 functions somewhat as well.

  I also made most of the internal SSL-dependent functions (using Curl_ssl_
  prefix) #defined to nothing when no SSL support is requested - previously
  they would unnecessarily call mostly empty functions.

lib/ssluse.h

@@ -7,7 +7,7 @@
  *                            | (__| |_| |  _ <| |___
  *                             \___|\___/|_| \_\_____|
  *
- * Copyright (C) 1998 - 2007, Daniel Stenberg, <daniel@haxx.se>, et al.
+ * Copyright (C) 1998 - 2008, Daniel Stenberg, <daniel@haxx.se>, et al.
  *
  * This software is licensed as described in the file COPYING, which
  * you should have received as part of this distribution. The terms
@@ -23,6 +23,7 @@
  * $Id$
  ***************************************************************************/
 
+#ifdef USE_SSLEAY
 /*
  * This header should only be needed to get included by sslgen.c and ssluse.c
  */
@@ -71,5 +72,26 @@ int Curl_ossl_check_cxn(struct connectdata *cxn);
 int Curl_ossl_seed(struct SessionHandle *data);
 
 int Curl_ossl_shutdown(struct connectdata *conn, int sockindex);
+bool Curl_ossl_data_pending(const struct connectdata *conn,
+                            int connindex);
 
+/* API setup for OpenSSL */
+#define curlssl_init Curl_ossl_init
+#define curlssl_cleanup Curl_ossl_cleanup
+#define curlssl_connect Curl_ossl_connect
+#define curlssl_connect_nonblocking Curl_ossl_connect_nonblocking
+#define curlssl_session_free(x) Curl_ossl_session_free(x)
+#define curlssl_close_all Curl_ossl_close_all
+#define curlssl_close Curl_ossl_close
+#define curlssl_shutdown(x,y) Curl_ossl_shutdown(x,y)
+#define curlssl_set_engine(x,y) Curl_ossl_set_engine(x,y)
+#define curlssl_set_engine_default(x) Curl_ossl_set_engine_default(x)
+#define curlssl_engines_list(x) Curl_ossl_engines_list(x)
+#define curlssl_send Curl_ossl_send
+#define curlssl_recv Curl_ossl_recv
+#define curlssl_version Curl_ossl_version
+#define curlssl_check_cxn Curl_ossl_check_cxn
+#define curlssl_data_pending(x,y) Curl_ossl_data_pending(x,y)
+
+#endif /* USE_SSLEAY */
 #endif