Migrate project created with templates provided with WinCC OA 3.21.4 or older

Due to significant refactoring in WinCC OA 3.21.5, existing Backend projects require manual migration. This involves updating CMake library links, adding the MSVC runtime policy, adjusting subdirectory calls, and rebuilding after cleaning external libraries.

In WinCC OA 3.21.5 the template for Backend project was significantly refactored. It is necessary to migrate Backend projects to remain compatible with new WinCC OA release. Automatic migration procedure is not provided, because the affected files could contain adaptations introduced during Backend project development. What follows is a list of necessary project changes.

Adapt

target_link_libraries

call in

Lib/CMakeLists.txt

change zeromq to libzmq - add libcppzmq - change protobuf to libprotobuf

Example, before:

target_link_libraries(${TARGET} 
  ${WCCOA_LIB_PREFIX}Basics${WCCOA_LIB_INFIX} 
  CommonBackend 
  ${SSL_LIB} 
  Importer 
  NgaProtobufFiles 
  CommonMultiplexer 
  DpeNameMapper 
  zeromq 
  protobuf )

After:

target_link_libraries(${TARGET} 
  ${WCCOA_LIB_PREFIX}Basics${WCCOA_LIB_INFIX} 
  CommonBackend
   ${SSL_LIB} 
  Importer 
  NgaProtobufFiles 
  CommonMultiplexer 
  DpeNameMapper 
  libzmq 
  libcppzmq 
  libprotobuf 
  )

Adapt CMakeLists.txt file in the root of the project directory by adding this snippet just after cmake_minimum_required call at the beginning:

if ( WIN32 ) 
  # MSVC runtime library flags are selected by an abstraction.
  cmake_policy(SET CMP0091 NEW) 
  set(CMAKE_MSVC_RUNTIME_LIBRARY "MultiThreadedDLL" CACHE STRING "" FORCE) ## on Windows always use the non-debug runtime libs (-MD)
endif()

Additionally, near the end of the file change add_subdirectory(ExternLibs) into
```
add_subdirectory(${API_ROOT}/TemplateNextGenArchBackend/ExternLibs ${CMAKE_CURRENT_BINARY_DIR}/ExternLibs)
```
The
```
updateNextGenArchExternLibs.cmd 
```
or
```
updateNextGenArchExternLibs.sh
```
script can be removed, it is no longer necessary. Updates to external dependencies are now managed by the cmake build process and will be available automatically after WinCC OA upgrade.
The
```
ExternLibs
```
subdirectory together with its contents is no longer used by the project and can be removed.

Remove the old `build` subdirectory and regenerate it:

cd build
cmake -G "Visual Studio 17 2022" -A "x64" -T "v143" -D CMAKE_BUILD_TYPE=RelWithDebInfo -D CMAKE_CONFIGURATION_TYPES=RelWithDebInfo ..

or on Linux:

cmake -D CMAKE_BUILD_TYPE=RelWithDebInfo ..

Now the project can be built:
```
cmake --build . --config RelWithDebInfo
```