Clean up a list of dead link about C++ (#3963)

free-programming-books-zh.md

@@ -321,7 +321,6 @@
 ### C
 
 * [C 语言常见问题集](http://c-faq-chn.sourceforge.net/ccfaq/ccfaq.html)
-* [C/C++ 学习教程](http://doc.lellansin.com)
 * [Linux C 编程一站式学习](http://docs.linuxtone.org/ebooks/C&CPP/c/)
 * [新概念 C 语言教程](https://github.com/limingth/NCCL)
 
@@ -340,18 +339,14 @@
 * [C++ FAQ LITE(中文版)](http://www.sunistudio.com/cppfaq/)
 * [C++ Primer 5th Answers](https://github.com/Mooophy/Cpp-Primer)
 * [C++ Template 进阶指南](https://github.com/wuye9036/CppTemplateTutorial)
-* [C++ 基础教程](http://www.prglab.com/cms/)
-* [C++ 并发编程(基于C++11)](https://chenxiaowei.gitbooks.io/cpp_concurrency_in_action/content/)
 * [C++ 并发编程指南](https://github.com/forhappy/Cplusplus-Concurrency-In-Practice)
 * [CGDB中文手册](https://github.com/leeyiw/cgdb-manual-in-chinese)
 * [Cmake 实践](https://web.archive.org/web/20170615174144/http://sewm.pku.edu.cn/src/paradise/reference/CMake%20Practice.pdf) (PDF)
 * [GNU make 指南](http://docs.huihoo.com/gnu/linux/gmake.html)
 * [Google C++ 风格指南](http://zh-google-styleguide.readthedocs.org/en/latest/google-cpp-styleguide/contents/)
-* [QT 教程](http://www.kuqin.com/qtdocument/tutorial.html)
 * [ZMQ 指南](https://github.com/anjuke/zguide-cn)
 * [像计算机科学家一样思考（C++版)](http://www.ituring.com.cn/book/1203) (《How To Think Like a Computer Scientist: C++ Version》中文版)
 * [简单易懂的C魔法](http://www.nowamagic.net/librarys/books/contents/c)
-* [跟我一起写Makefile](http://scc.qibebt.cas.cn/docs/linux/base/%B8%FA%CE%D2%D2%BB%C6%F0%D0%B4Makefile-%B3%C2%F0%A9.pdf) (PDF)
 
 
 ### CoffeeScript