Inconsistent ExtendedToStr, FloatToStrF and Format.

TruncBug.dpr

// http://forum.lazarus.freepascal.org/index.php/topic,42487.0.html

{$IFDEF FPC}{$MODE DELPHI}{$ENDIF}
{$IFOPT D+} {$DEFINE DEBUG} {$ENDIF}
{$ASSERTIONS ON}
program TruncBug;
{$IFNDEF FPC}{$APPTYPE CONSOLE}{$ENDIF}
uses
  SysUtils;

var
  A,B: Extended;
begin
  A := 0.3050;
  B := 0.6659963050;

  (*          FPC 3.1.1-r39514     Delphi7              Delphi25Tokyo
     Win32:   0.31; 0.66599630     0.31; 0.66599631     0.31; 0.66599631
     Win64:   0.31; 0.66599631                          0.31; 0.66599631
     Lnx64:   0.31; 0.66599630
  *)
  Writeln(FloatToStrF(A, ffFixed, 20, 2) + '; '+ FloatToStrF(B, ffFixed, 20, 8));

  (*          FPC 3.1.1-r39514     Delphi7              Delphi25Tokyo
     Win32:   0.31; 0.66599630     0.31; 0.66599631     0.31; 0.66599631
     Win64:   0.31; 0.66599631                          0.31; 0.66599631
     Lnx64:   0.31; 0.66599630
  *)
  Writeln(Format('%.2n; %.8n',[A,B]));
end.                                               

TruncBugSyn.dpr

{$IFDEF FPC}{$MODE DELPHI}{$ENDIF}
{$IFOPT D+} {$DEFINE DEBUG} {$ENDIF}
{$ASSERTIONS ON}
program TruncBugSyn;
{$IFNDEF FPC}{$APPTYPE CONSOLE}{$ENDIF}
uses
  SysUtils,
  SynCommons;

var
  A,B: Extended;
begin
  A := 0.3050;
  B := 0.6659963050;

  (*          FPC 3.1.1-r39514     Delphi7              Delphi25Tokyo
     Win32:   0; 0.6659963         0.31; 0.66599631     0.31; 0.66599631
     Win64:   0; 0.6659963                              0; 0.6659963
     Lnx64:   0; 0.6659963
  *)
  Writeln(ExtendedToStr(A, 2) + '; '+ ExtendedToStr(B, 8));

  (*          FPC 3.1.1-r39514     Delphi7              Delphi25Tokyo
     Win32:   0.305; 0.665996305   0.305; 0.665996305   0.305; 0.665996305
     Win64:   0.305; 0.665996305                        0.305; 0.665996305
     Lnx64:   0.305; 0.665996305
  *)
  Writeln(FormatUTF8('%; %', [A,B]));

  (*          FPC 3.1.1-r39514     Delphi7              Delphi25Tokyo
     Win32:   0.31; 0.66599630     0.31; 0.66599631     0.31; 0.66599631
     Win64:   0.31; 0.66599631                          0.31; 0.66599631
     Lnx64:   0.31; 0.66599630
  *)
  Writeln(FloatToStrF(A, ffFixed, 20, 2) + '; '+ FloatToStrF(B, ffFixed, 20, 8));

  (*          FPC 3.1.1-r39514     Delphi7              Delphi25Tokyo
     Win32:   0.31; 0.66599630     0.31; 0.66599631     0.31; 0.66599631
     Win64:   0.31; 0.66599631                          0.31; 0.66599631
     Lnx64:   0.31; 0.66599630
  *)
  Writeln(Format('%.2n; %.8n',[A,B]));
end.