vim-patch:8.1.2341: not so easy to interrupt a script programatically

Problem:    Not so easy to interrupt a script programatically.
Solution:   Add the interrupt() function. (Yasuhiro Matsumoto, closes vim/vim#2834)
67a2deb9cb

src/nvim/eval/funcs.c

@@ -4717,6 +4717,14 @@ static void f_insert(typval_T *argvars, typval_T *rettv, FunPtr fptr)
   }
 }
 
+// "interrupt()" function
+static void f_interrupt(typval_T *argvars FUNC_ATTR_UNUSED,
+                        typval_T *rettv FUNC_ATTR_UNUSED,
+                        FunPtr fptr FUNC_ATTR_UNUSED)
+{
+  got_int = true;
+}
+
 /*
  * "invert(expr)" function
  */