patch 9.0.1150: :interface is not implemented yet
Problem: :interface is not implemented yet.
Solution: Implement the basics of :interface.
diff --git a/src/proto/userfunc.pro b/src/proto/userfunc.pro
index e3470f6..a87113f 100644
--- a/src/proto/userfunc.pro
+++ b/src/proto/userfunc.pro
@@ -46,7 +46,7 @@
char_u *alloc_printable_func_name(char_u *fname);
char_u *save_function_name(char_u **name, int *is_global, int skip, int flags, funcdict_T *fudi);
void list_functions(regmatch_T *regmatch);
-ufunc_T *define_function(exarg_T *eap, char_u *name_arg, garray_T *lines_to_free, int in_class);
+ufunc_T *define_function(exarg_T *eap, char_u *name_arg, garray_T *lines_to_free, int class_flags);
void ex_function(exarg_T *eap);
ufunc_T *find_func_by_name(char_u *name, compiletype_T *compile_type);
void ex_defcompile(exarg_T *eap);