Updates needed after upgrading PngComponents

Source commit: f76dde95f53346d6064fc791000762f249445c69

source/packages/png/PngBitBtn.pas

@@ -8,9 +8,11 @@ uses
 type
   TPngBitBtn = class(TBitBtn)
 {$IF RTLVersion >= 24.0 }
+{$IFNDEF BCB}
   strict private
     class constructor Create;
     class destructor Destroy;
+{$IFEND}
 {$IFEND}
   private
     FPngImage: TPngImage;
@@ -83,6 +85,7 @@ end;
 { TPngBitBtn }
 
 {$IF RTLVersion >= 24.0 }
+{$IFNDEF BCB}
 class constructor TPngBitBtn.Create;
 begin
   TCustomStyleEngine.RegisterStyleHook(TPngBitBtn, TPngBitBtnStyleHook);
@@ -93,6 +96,7 @@ begin
   TCustomStyleEngine.UnRegisterStyleHook(TPngBitBtn, TPngBitBtnStyleHook);
 end;
 {$IFEND}
+{$IFEND}
 
 constructor TPngBitBtn.Create(AOwner: TComponent);
 begin

source/packages/png/PngFunctions.pas

@@ -216,7 +216,6 @@ var
     BitsSize: Integer;
     bmpDC: HDC;
     bmpHandle: HBITMAP;
-    scanlineLength: Integer;
   begin
     BitsSize := 4 * SourceColor.Width * SourceColor.Height;
     Bits := AllocMem(BitsSize);

source/packages/png/PngImageList.pas

@@ -477,13 +477,12 @@ var
   Png: TPngImage;
 begin
   if TObject(Self) is TPngImageList then begin
-    // MP
-    Png := nil;
+    Png := TPngImage.Create;
     try
       CreatePNGMasked(Image, MaskColor, Png);
       result := AddPng(Png);
     finally
-      if Assigned(Png) then Png.Free;
+      Png.Free;
     end;
   end
   else begin