diff --git a/libsyncthing/CMakeLists.txt b/libsyncthing/CMakeLists.txt
index 18c1596..7b28960 100644
--- a/libsyncthing/CMakeLists.txt
+++ b/libsyncthing/CMakeLists.txt
@@ -119,8 +119,14 @@ list(APPEND PRIVATE_INCLUDE_DIRS "${SYNCTHING_PATH}/cmd/syncthing")
 # find c++utilities
 find_package(c++utilities${CONFIGURATION_PACKAGE_SUFFIX} 5.0.0 REQUIRED)
 list(APPEND CMAKE_MODULE_PATH ${CPP_UTILITIES_MODULE_DIRS})
-list(APPEND PRIVATE_SHARED_INCLUDE_DIRS ${CPP_UTILITIES_INCLUDE_DIRS})
-list(APPEND PRIVATE_STATIC_INCLUDE_DIRS ${CPP_UTILITIES_INCLUDE_DIRS})
+if (CPP_UTILITIES_SOURCE_DIR)
+    list(APPEND PRIVATE_INCLUDE_DIRS
+        $<BUILD_INTERFACE:${CPP_UTILITIES_SOURCE_DIR}/..>
+        $<INSTALL_INTERFACE:${CPP_UTILITIES_INCLUDE_DIRS}>
+    )
+else ()
+    list(APPEND PRIVATE_INCLUDE_DIRS ${CPP_UTILITIES_INCLUDE_DIRS})
+endif ()
 
 # use std::filesystem
 use_standard_filesystem()