Work around MSVC 2019 16.9.0 warning C4103 compiler bug

With that compiler version (and --with-latest-c++), the build now started to
fail for me with

> [build CXX] slideshow/source/engine/opengl/Operation.cxx
> C:\PROGRA~2\MIB055~1\2019\COMMUN~1\VC\Tools\MSVC\1428~1.299\Include\memory(14): error C2220: the following warning is treated as an error
> C:\PROGRA~2\MIB055~1\2019\COMMUN~1\VC\Tools\MSVC\1428~1.299\Include\memory(14): warning C4103: alignment changed after including header, may be due to missing #pragma pack(pop)
> C:\lo\core\slideshow\source\engine\opengl\Operation.hxx(34): warning C4103: alignment changed after including header, may be due to missing #pragma pack(pop)
> C:/lo/core/slideshow/source/engine/opengl/Operation.cxx(36): warning C4103: alignment changed after including header, may be due to missing #pragma pack(pop)

Mike had experienced the same (though without --with-latest-c++, but due to us
now always using /permissive-) as explained in the post-merge comments starting
at <https://gerrit.libreoffice.org/c/core/+/108961/4#
message-cc2a1e2ebaeb96cbacd7d13d57ffc701f2ed4608> "Use MSVC's /permissive- to
make it more standards conforming", linking to
<https://developercommunity.visualstudio.com/t/
warning-c4103-in-visual-studio-166-update/1057589> "Warning C4103 in Visual
Studio 16.6 Update".

At least for my --with-latest-c++ aka /std:c++latest case, I have reduced the
issue to a test.cc of

> #include <cmath>
> template<typename> void f(int[1]) {}
> #include <exception>

failing with

> **********************************************************************
> ** Visual Studio 2019 Developer Command Prompt v16.9.0
> ** Copyright (c) 2021 Microsoft Corporation
> **********************************************************************
> [vcvarsall.bat] Environment initialized for: 'x64'
>
> C:\Program Files (x86)\Microsoft Visual Studio\2019\Community>cd \lo\core
>
> C:\test>cl /std:c++latest /c test.cc
> Microsoft (R) C/C++ Optimizing Compiler Version 19.28.29910 for x64
> Copyright (C) Microsoft Corporation.  All rights reserved.
>
> /std:c++latest is provided as a preview of language features from the latest C++
>
> working draft, and we're eager to hear about bugs and suggestions for improvemen
> ts.
> However, note that these features are provided as-is without support, and subjec
> t
> to changes or removal as the working draft evolves. See
> https://go.microsoft.com/fwlink/?linkid=2045807 for details.
>
> test.cc
> test.cc(3): warning C4103: alignment changed after including header, may be due
> to missing #pragma pack(pop)

which looks clearly like a compiler bug.

As it happens, reordering the includes here makes the issue disappear at least
for me.

Change-Id: Ib3d0756b38da4f24e62cafa900b44c8ec8e842b0
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/112317
Tested-by: Jenkins
Reviewed-by: Stephan Bergmann <sbergman@redhat.com>

1 files changed, 2 insertions, 2 deletions

diff --git a/slideshow/source/engine/opengl/Operation.cxx b/slideshow/source/engine/opengl/Operation.cxx
index e70f203edad7..ec83d6b74c32 100644
--- a/slideshow/source/engine/opengl/Operation.cxx
+++ b/slideshow/source/engine/opengl/Operation.cxx
@@ -28,13 +28,13 @@
 
 #include <sal/config.h>
 
+#include "Operation.hxx"
+
 #include <basegfx/numeric/ftools.hxx>
 
 #include <glm/gtc/matrix_transform.hpp>
 #include <glm/gtc/type_ptr.hpp>
 
-#include "Operation.hxx"
-
 SRotate::SRotate(const glm::vec3& Axis, const glm::vec3& Origin,
         double Angle, bool bInter, double T0, double T1):
     Operation(bInter, T0, T1),