PRTL_SPLAY_LINKS
RtlRealPredecessor(
  IN  PRTL_SPLAY_LINKS Links
  );

Routine Description:

    The RealPredecessor function takes as input a pointer to a splay link
    in a tree and returns a pointer to the predecessor of the input node
    within the entire tree.  If there is not a predecessor, the return value
    is NULL.

Arguments:

    Links - Supplies a pointer to a splay link in a tree.

Return Value:

    PRTL_SPLAY_LINKS - returns a pointer to the predecessor in the entire tree