libssh2_session_startup(3) => libssh2_session_handshake(3)

Propagate for the current function in docs and examples.
libssh2_session_startup() is deprecated.

example/ssh2_agent.c

@@ -94,7 +94,7 @@ int main(int argc, char *argv[])
      * banners, exchange keys, and setup crypto, compression, and MAC layers
      */
     session = libssh2_session_init();
-    if (libssh2_session_startup(session, sock)) {
+    if (libssh2_session_handshake(session, sock)) {
         fprintf(stderr, "Failure establishing SSH session\n");
         return 1;
     }