sasl_gssapi: Added Curl_sasl_build_gssapi_spn() function

#include "curl_sasl.h"

#include "urldata.h"

#define _MPRINTF_REPLACE /* use our functions only */

#include <curl/mprintf.h>

/* The last #include file should be: */

#include "memdebug.h"

/*

* Curl_sasl_build_gssapi_spn()

*

* This is used to build a SPN string in the format service@host.

*

* Parameters:

*

* serivce  [in] - The service type such as www, smtp, pop or imap.

* host     [in] - The host name or realm.

*

* Returns a pointer to the newly allocated SPN.

*/

static char *Curl_sasl_build_gssapi_spn(const char *service, const char *host)

{

  /* Generate and return our SPN */

  return aprintf("%s@%s", service, host);

}

/*

 * Curl_sasl_create_gssapi_user_message()

 *