CP-7111: Fixing compilation warning to declare tmp variable as const.

Signed-off-by: Frediano Ziglio <frediano.ziglio@citrix.com>
Reviewed-by: Rob Dobson <rob.dobson@citrix.com>
CP-7111: Newer OpenSSL libraries handle stacks in a slightly different way. Adding ifdef construct to handle both old/new cases.

Signed-off-by: Frediano Ziglio <frediano.ziglio@citrix.com>
Signed-off-by: Rob Dobson <rob.dobson@citrix.com>