Remove libretro core - core will now be maintained by libretro

libretro have agreed to take over maintenance of the core.

Please see their fork at https://github.com/libretro/duckstation if you
wish to continue to use it.

src/frontend-common/CMakeLists.txt

@@ -1,6 +1,24 @@
 add_library(frontend-common
+  common_host_interface.cpp
+  common_host_interface.h
+  controller_interface.cpp
+  controller_interface.h
+  cubeb_audio_stream.cpp
+  cubeb_audio_stream.h
+  game_list.cpp
+  game_list.h
   game_settings.cpp
   game_settings.h
+  icon.cpp
+  icon.h
+  ini_settings_interface.cpp
+  ini_settings_interface.h
+  imgui_impl_opengl3.cpp
+  imgui_impl_opengl3.h
+  imgui_impl_vulkan.cpp
+  imgui_impl_vulkan.h
+  imgui_styles.cpp
+  imgui_styles.h  
   opengl_host_display.cpp
   opengl_host_display.h
   postprocessing_chain.cpp
@@ -9,97 +27,55 @@ add_library(frontend-common
   postprocessing_shader.h
   postprocessing_shadergen.cpp
   postprocessing_shadergen.h
+  save_state_selector_ui.cpp
+  save_state_selector_ui.h
   vulkan_host_display.cpp
   vulkan_host_display.h
 )
 
-target_link_libraries(frontend-common PUBLIC core common glad vulkan-loader)
+target_compile_definitions(frontend-common PRIVATE "WITH_IMGUI=1")
+target_link_libraries(frontend-common PUBLIC core common glad vulkan-loader cubeb imgui simpleini tinyxml2 scmversion)
 
 if(WIN32)
   target_sources(frontend-common PRIVATE
     d3d11_host_display.cpp
     d3d11_host_display.h
+    dinput_controller_interface.cpp
+    dinput_controller_interface.h
+    imgui_impl_dx11.cpp
+    imgui_impl_dx11.h
+    xinput_controller_interface.cpp
+    xinput_controller_interface.h
   )
   target_link_libraries(frontend-common PRIVATE d3d11.lib dxgi.lib)
 endif()
 
-if(NOT BUILD_LIBRETRO_CORE)
-  target_sources(frontend-common PRIVATE
-    imgui_impl_opengl3.h
-    imgui_impl_opengl3.cpp
-  )
-
-  target_sources(frontend-common PRIVATE
-    imgui_impl_vulkan.h
-    imgui_impl_vulkan.cpp
+if(SDL2_FOUND)
+  target_sources(frontend-common PRIVATE 
+    sdl_audio_stream.cpp
+    sdl_audio_stream.h
+    sdl_controller_interface.cpp
+    sdl_controller_interface.h
+    sdl_initializer.cpp
+    sdl_initializer.h
   )
+  target_compile_definitions(frontend-common PUBLIC "WITH_SDL2=1")
+  target_include_directories(frontend-common PRIVATE ${SDL2_INCLUDE_DIRS})
+  target_link_libraries(frontend-common PRIVATE ${SDL2_LIBRARIES})
 
+  # Copy bundled SDL2 to output on Windows.
   if(WIN32)
-    target_sources(frontend-common PRIVATE
-      imgui_impl_dx11.h
-      imgui_impl_dx11.cpp
-    )
+    add_custom_command(TARGET frontend-common POST_BUILD
+      COMMAND ${CMAKE_COMMAND} -E copy_if_different "${SDL2_DLL_PATH}" "${CMAKE_RUNTIME_OUTPUT_DIRECTORY}/SDL2.dll")
   endif()
-
-  target_sources(frontend-common PRIVATE
-    common_host_interface.cpp
-    common_host_interface.h
-    controller_interface.cpp
-    controller_interface.h
-    cubeb_audio_stream.cpp
-    cubeb_audio_stream.h
-    game_list.cpp
-    game_list.h
-    icon.cpp
-    icon.h
-    imgui_styles.cpp
-    imgui_styles.h
-    ini_settings_interface.cpp
-    ini_settings_interface.h
-    save_state_selector_ui.cpp
-    save_state_selector_ui.h
-  )
-
-  if(WIN32)
-    target_sources(frontend-common PRIVATE
-      dinput_controller_interface.cpp
-      dinput_controller_interface.h
-      xinput_controller_interface.cpp
-      xinput_controller_interface.h
-    )
-  endif()
-
-  target_compile_definitions(frontend-common PRIVATE "WITH_IMGUI=1")
-  target_link_libraries(frontend-common PUBLIC cubeb imgui simpleini tinyxml2 scmversion)
-
-  if(SDL2_FOUND)
-    target_sources(frontend-common PRIVATE 
-      sdl_audio_stream.cpp
-      sdl_audio_stream.h
-      sdl_controller_interface.cpp
-      sdl_controller_interface.h
-      sdl_initializer.cpp
-      sdl_initializer.h
-    )
-    target_compile_definitions(frontend-common PUBLIC "WITH_SDL2=1")
-    target_include_directories(frontend-common PRIVATE ${SDL2_INCLUDE_DIRS})
-    target_link_libraries(frontend-common PRIVATE ${SDL2_LIBRARIES})
-
-    # Copy bundled SDL2 to output on Windows.
-    if(WIN32)
-      add_custom_command(TARGET frontend-common POST_BUILD
-        COMMAND ${CMAKE_COMMAND} -E copy_if_different "${SDL2_DLL_PATH}" "${CMAKE_RUNTIME_OUTPUT_DIRECTORY}/SDL2.dll")
-    endif()
-  endif()
-
-  if(ENABLE_DISCORD_PRESENCE AND NOT BUILD_LIBRETRO_CORE)
-    target_compile_definitions(frontend-common PUBLIC -DWITH_DISCORD_PRESENCE=1)
-    target_link_libraries(frontend-common PRIVATE discord-rpc)
-  endif()
-
-  # Copy the provided data directory to the output directory.
-  add_custom_command(TARGET frontend-common POST_BUILD
-    COMMAND ${CMAKE_COMMAND} -E copy_directory "${CMAKE_SOURCE_DIR}/data" "${CMAKE_RUNTIME_OUTPUT_DIRECTORY}"
-  )
 endif()
 
+if(ENABLE_DISCORD_PRESENCE)
+  target_compile_definitions(frontend-common PUBLIC -DWITH_DISCORD_PRESENCE=1)
+  target_link_libraries(frontend-common PRIVATE discord-rpc)
+endif()
+
+# Copy the provided data directory to the output directory.
+add_custom_command(TARGET frontend-common POST_BUILD
+  COMMAND ${CMAKE_COMMAND} -E copy_directory "${CMAKE_SOURCE_DIR}/data" "${CMAKE_RUNTIME_OUTPUT_DIRECTORY}"
+)