Add portable Windows build and update GC runtime

apps/desktop/CMakeLists.txt

@@ -17,6 +17,11 @@ target_link_libraries(openroller-desktop
         Vectorail::GCEffects
 )
 
+if(MINGW AND CMAKE_CXX_COMPILER_ID STREQUAL "GNU")
+    target_link_options(openroller-desktop PRIVATE
+        -static -static-libgcc -static-libstdc++)
+endif()
+
 if(MSVC)
     target_compile_options(openroller-desktop PRIVATE /W4)
 else()
@@ -25,3 +30,27 @@ endif()
 
 configure_file(openroller.cfg openroller.cfg COPYONLY)
 file(COPY shaders DESTINATION "${CMAKE_CURRENT_BINARY_DIR}")
+
+add_custom_command(TARGET openroller-desktop POST_BUILD
+    COMMAND ${CMAKE_COMMAND} -E copy_directory
+        "${CMAKE_CURRENT_SOURCE_DIR}/shaders"
+        "$<TARGET_FILE_DIR:openroller-desktop>/shaders"
+    COMMAND ${CMAKE_COMMAND} -E copy_if_different
+        "${CMAKE_CURRENT_SOURCE_DIR}/openroller.cfg"
+        "$<TARGET_FILE_DIR:openroller-desktop>/openroller.cfg"
+    VERBATIM
+)
+
+if(WIN32 AND TARGET SDL3::SDL3-shared)
+    add_custom_command(TARGET openroller-desktop POST_BUILD
+        COMMAND ${CMAKE_COMMAND} -E copy_if_different
+            "$<TARGET_FILE:SDL3::SDL3-shared>"
+            "$<TARGET_FILE_DIR:openroller-desktop>"
+        VERBATIM
+    )
+    install(FILES "$<TARGET_FILE:SDL3::SDL3-shared>" DESTINATION .)
+endif()
+
+install(TARGETS openroller-desktop RUNTIME DESTINATION .)
+install(DIRECTORY shaders DESTINATION .)
+install(FILES openroller.cfg DESTINATION .)