diff --git a/src/3rdparty/CMakeLists.txt b/src/3rdparty/CMakeLists.txt
--- a/src/3rdparty/CMakeLists.txt
+++ b/src/3rdparty/CMakeLists.txt
@@ -1,5 +1,6 @@
 add_subdirectory(catch2)
 add_subdirectory(fmt)
+add_subdirectory(icu)
 add_subdirectory(md5)
 add_subdirectory(squirrel)
 add_subdirectory(opengl)