Merge branch 'V5-6-patches' into V5-7-patches

* V5-6-patches:
  CHANGES: BUG: 2568: Avoid that file descriptors above FD_SETSIZE trigger abort()
  When enlarging a large_fd_set, use FD_ZERO if possible
  Fixed a Solaris-specific compiler warning.
  Ensure that fdset structure is resized sufficiently to accomodate the specified socket ID. Problem reported by Shiyalei.