patch 8.2.2188: Vim9: crash when calling global function from :def function

Problem:    Vim9: crash when calling global function from :def function.
Solution:   Set the outer context.  Define the partial for the context on the
            original function. Use a refcount to keep track of which ufunc is
            using a dfunc. (closes #7525)
diff --git a/src/proto/userfunc.pro b/src/proto/userfunc.pro
index c79c101..da4a880 100644
--- a/src/proto/userfunc.pro
+++ b/src/proto/userfunc.pro
@@ -13,7 +13,7 @@
 ufunc_T *find_func(char_u *name, int is_global, cctx_T *cctx);
 int func_is_global(ufunc_T *ufunc);
 int func_name_refcount(char_u *name);
-ufunc_T *copy_func(char_u *lambda, char_u *global);
+int copy_func(char_u *lambda, char_u *global, ectx_T *ectx);
 int funcdepth_increment(void);
 void funcdepth_decrement(void);
 int funcdepth_get(void);