EmptyBPixel is unused

...since b62826ad "Remove more unused methods"

BPixel was marked BASEGFX_DLLPUBLIC, but all its member functions are defined
inline in include/basegfx/pixel/bpixel.hxx, and basegfx/source/pixel/bpixel.cxx
was the only .cxx from Library_basegfx that included it.  So on Windows, non-
inline implementations of the BPixel member functions are no longer exported
from Library_basegfx, even though code in drawinglayer using BPixel expects that
(and would thus start to fail to link on Windows).  So just not mark that all-
inline BPixel class as DLLPUBLIC.

Change-Id: I7553a7ac5a57b5d175d7c81b3908ad7b80b064c3
Reviewed-on: https://gerrit.libreoffice.org/66043
Tested-by: Jenkins
Reviewed-by: Stephan Bergmann <sbergman@redhat.com>

basegfx/Library_basegfx.mk

@@ -40,7 +40,6 @@ $(eval $(call gb_Library_add_exception_objects,basegfx,\
     basegfx/source/matrix/b3dhommatrix \
     basegfx/source/matrix/b3dhommatrixtools \
 	basegfx/source/numeric/ftools \
-    basegfx/source/pixel/bpixel \
     basegfx/source/point/b2dpoint \
     basegfx/source/point/b2ipoint \
     basegfx/source/point/b3dpoint \

basegfx/source/pixel/bpixel.cxx

-/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
-/*
- * This file is part of the LibreOffice project.
- *
- * This Source Code Form is subject to the terms of the Mozilla Public
- * License, v. 2.0. If a copy of the MPL was not distributed with this
- * file, You can obtain one at http://mozilla.org/MPL/2.0/.
- *
- * This file incorporates work covered by the following license notice:
- *
- * Licensed to the Apache Software Foundation (ASF) under one or more
- * contributor license agreements. See the NOTICE file distributed
- * with this work for additional information regarding copyright
- * ownership. The ASF licenses this file to you under the Apache
- * License, Version 2.0 (the "License"); you may not use this file
- * except in compliance with the License. You may obtain a copy of
- * the License at http://www.apache.org/licenses/LICENSE-2.0 .
- */
-
-#include <basegfx/pixel/bpixel.hxx>
-#include <rtl/instance.hxx>
-
-namespace { struct EmptyBPixel : public rtl::Static<basegfx::BPixel, EmptyBPixel> {}; }
-
-/* vim:set shiftwidth=4 softtabstop=4 expandtab: */

include/basegfx/pixel/bpixel.hxx

@@ -26,7 +26,7 @@
 
 namespace basegfx
 {
-    class BASEGFX_DLLPUBLIC BPixel final
+    class BPixel final
     {
         union
         {