Add ssl_cleanup to free memory

* src/ssl.h: Add declaration for ssl_cleanup.
* src/openssl.c: Add ssl_cleanup stub.
* src/gnutls.c: Implement ssl_cleanup.

src/gnutls.c

@@ -226,6 +226,15 @@ cert to be of the same type.\n"));
   return true;
 }
 
+void
+ssl_cleanup (void)
+{
+  if (credentials)
+    gnutls_certificate_free_credentials(credentials);
+
+  gnutls_global_deinit();
+}
+
 struct wgnutls_transport_context
 {
   gnutls_session_t session;       /* GnuTLS session handle */

src/openssl.c

@@ -415,6 +415,11 @@ ssl_init (void)
   return false;
 }
 
+void
+ssl_cleanup (void)
+{
+}
+
 struct openssl_transport_context
 {
   SSL *conn;                    /* SSL connection handle */

src/ssl.h

@@ -33,6 +33,7 @@ as that of the covered work.  */
 #define GEN_SSLFUNC_H
 
 bool ssl_init (void);
+void ssl_cleanup (void);
 bool ssl_connect_wget (int, const char *, int *);
 bool ssl_check_certificate (int, const char *);