diff --git a/src/proto/indent.pro b/src/proto/indent.pro
index 2702f40..5ab338d 100644
--- a/src/proto/indent.pro
+++ b/src/proto/indent.pro
@@ -31,6 +31,7 @@
 int get_expr_indent(void);
 int get_lisp_indent(void);
 void fixthisline(int (*get_the_indent)(void));
+int use_indentexpr_for_lisp(void);
 void fix_indent(void);
 void f_indent(typval_T *argvars, typval_T *rettv);
 void f_lispindent(typval_T *argvars, typval_T *rettv);