Description of problem:
Default_Bit_Order for ppc64le (little endian architecture) is set to 
   Default_Bit_Order : constant Bit_Order := High_Order_First;
while shoult be
   Default_Bit_Order : constant Bit_Order := Low_Order_First;

Which leads to incorrect configuration of applications which use this value.


Version-Release number of selected component (if applicable):
gcc-6.3.1-1.fc25.ppc64le
gcc-gnat-6.3.1-1.fc25.ppc64le
rawhide/f26 affected as well so set version to f26

How reproducible:
100%

Steps to Reproduce:
Code:
with Ada.Text_IO;
with System; use System;
procedure Test is
	type Rec is record
		Age : Integer;
	end record;
begin
   Ada.Text_IO.Put_Line("Default byte order is: " & Bit_Order'Image ( Default_Bit_Order));
   Ada.Text_IO.Put_Line("Order of record is " & Bit_Order'Image ( Bit_Order'Bit_Order));
end Test;

Output:
Default byte order is: HIGH_ORDER_FIRST
Order of record is LOW_ORDER_FIRST