diff --git a/src/3rdparty/CMakeLists.txt b/src/3rdparty/CMakeLists.txt
--- a/src/3rdparty/CMakeLists.txt
+++ b/src/3rdparty/CMakeLists.txt
@@ -6,3 +6,4 @@ add_subdirectory(monocypher)
 add_subdirectory(squirrel)
 add_subdirectory(nlohmann)
 add_subdirectory(opengl)
+add_subdirectory(openttd_social_integration_api)