Split Windows app shell target

CMakeLists.txt

@@ -258,14 +258,32 @@ if(PP_BUILD_APP)
         set_source_files_properties(src/version.cpp
             PROPERTIES SKIP_PRECOMPILE_HEADERS ON)
 
+        add_library(panopainter_app INTERFACE)
+        target_link_libraries(panopainter_app
+            INTERFACE
+                pp_legacy_app)
+
+        add_library(pp_platform_windows OBJECT
+            ${PP_WINDOWS_PLATFORM_SOURCES})
+        target_link_libraries(pp_platform_windows
+            PUBLIC
+                panopainter_app
+            PRIVATE
+                pp_project_options
+                pp_project_warnings)
+        target_precompile_headers(pp_platform_windows REUSE_FROM pp_legacy_app)
+        set_target_properties(pp_platform_windows PROPERTIES
+            VS_GLOBAL_CharacterSet "Unicode")
+
         add_executable(PanoPainter WIN32
-            ${PP_WINDOWS_APP_SOURCES})
+            ${PP_WINDOWS_APP_SOURCES}
+            $<TARGET_OBJECTS:pp_platform_windows>)
 
         target_link_libraries(PanoPainter
             PRIVATE
                 pp_project_options
                 pp_project_warnings
-                pp_legacy_app
+                pp_platform_windows
                 "${CMAKE_CURRENT_SOURCE_DIR}/libs/bugtrap-client/lib/BugTrapU-x64.lib"
                 "$<$<CONFIG:Debug>:${CMAKE_CURRENT_SOURCE_DIR}/libs/curl-win/lib/dll-debug-x64/libcurl_debug.lib>"
                 "$<$<NOT:$<CONFIG:Debug>>:${CMAKE_CURRENT_SOURCE_DIR}/libs/curl-win/lib/dll-release-x64/libcurl.lib>"
@@ -282,7 +300,6 @@ if(PP_BUILD_APP)
                 user32
                 wbemuuid)
 
-        target_precompile_headers(PanoPainter REUSE_FROM pp_legacy_app)
         set_target_properties(PanoPainter PROPERTIES
             VS_GLOBAL_CharacterSet "Unicode")