diff --git a/external/xxtea/CMakeLists.txt b/external/xxtea/CMakeLists.txt
index 65ffbf702b..cf7ad364b2 100644
--- a/external/xxtea/CMakeLists.txt
+++ b/external/xxtea/CMakeLists.txt
@@ -1,5 +1,5 @@
 set(XXTEA
-  xxtea.c
+  xxtea.cpp
 )
 
 add_library(xxtea STATIC