diff --git a/lsplant/src/main/jni/CMakeLists.txt b/lsplant/src/main/jni/CMakeLists.txt
index 0459321ea..d96d31702 100644
--- a/lsplant/src/main/jni/CMakeLists.txt
+++ b/lsplant/src/main/jni/CMakeLists.txt
@@ -18,6 +18,8 @@ endif()
 set(SOURCES lsplant.cc)
 file(GLOB_RECURSE MODULE_SOURCES CONFIGURE_DEPENDS "*.cxx")
 file(GLOB_RECURSE MODULE_INTERFACES CONFIGURE_DEPENDS "*.ixx")
+list(FILTER MODULE_SOURCES EXCLUDE REGEX "${PROJECT_SOURCE_DIR}.external.+")
+list(FILTER MODULE_INTERFACES EXCLUDE REGEX "${PROJECT_SOURCE_DIR}.external.+")
 
 set(DEX_BUILDER_BUILD_SHARED OFF CACHE INTERNAL "" FORCE)
 add_subdirectory(external/dex_builder)