- Hans-Jurgen May pointed out that trying SCP or SFTP over a SOCKS proxy

crashed libcurl. This is now addressed by making sure we use "plain send"
  internally when doing the socks handshake instead of the Curl_write()
  function which is designed to use the "target" protocol. That's then SCP or
  SFTP in this case. I also took the opportunity and cleaned up some ssh-
  related #ifdefs in the code for readability.

lib/sendf.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
@@ -62,12 +62,18 @@ void Curl_read_rewind(struct connectdata *conn,
 int Curl_read(struct connectdata *conn, curl_socket_t sockfd,
               char *buf, size_t buffersize,
               ssize_t *n);
-/* internal write-function, does plain socket, SSL and krb4 */
+/* internal write-function, does plain socket, SSL, SCP, SFTP and krb4 */
 CURLcode Curl_write(struct connectdata *conn,
                     curl_socket_t sockfd,
                     const void *mem, size_t len,
                     ssize_t *written);
 
+/* internal write-function, does plain sockets ONLY */
+CURLcode Curl_write_plain(struct connectdata *conn,
+                          curl_socket_t sockfd,
+                          const void *mem, size_t len,
+                          ssize_t *written);
+
 /* the function used to output verbose information */
 int Curl_debug(struct SessionHandle *handle, curl_infotype type,
                char *data, size_t size,