考虑这个makefile：
.PHONY: all
all: dummy test
ulimit -s
include dummy
dummy: test
touch dummy
当我运行它时，我得到：
$ make -v
GNU Make 4.1
Built for x86_64-pc-linux-gnu
Copyright (C) 1988-2014 Free Software Foundation, Inc.
License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html>
This is free software: you are free to change and redistribute it.
There is NO WARRANTY, to the extent permitted by law.
$ touch test; make
touch dummy
ulimit -s
unlimited
但是，如果我删除include dummy或将touch dummy替换为true，则ulimit -s会8192。发生了什么事？