diff --git a/src/lua_polyobjlib.c b/src/lua_polyobjlib.c
index 6778b4240..9adaf1270 100644
--- a/src/lua_polyobjlib.c
+++ b/src/lua_polyobjlib.c
@@ -11,6 +11,7 @@
 /// \brief polyobject library for Lua scripting
 
 #include "doomdef.h"
+#include "fastcmp.h"
 #include "p_local.h"
 #include "p_polyobj.h"
 #include "lua_script.h"