YCM需要设置include path，如果设置的不正确会导致函数的定义不对或者fix错误，那如何设置正确的路径呢。
从stackoverflow上面搜到的答案，换成了类似的写法。
g++ -E -xc++ - -Wp,-v < /dev/null可以得到结果为
/usr/lib/gcc/x86_64-pc-linux-gnu/11.2.0/../../../../include/c++/11.2.0
/usr/lib/gcc/x86_64-pc-linux-gnu/11.2.0/../../../../include/c++/11.2.0/x86_64-pc-linux-gnu
/usr/lib/gcc/x86_64-pc-linux-gnu/11.2.0/../../../../include/c++/11.2.0/backward
/usr/lib/gcc/x86_64-pc-linux-gnu/11.2.0/include
/usr/local/include
/usr/lib/gcc/x86_64-pc-linux-gnu/11.2.0/include-fixed
/usr/include那么我们的.ycm_extra_config.py需要换成
'-isystem',
'/usr/include/c++/11.2.0',
'-isystem',
'/usr/include/c++/11.2.0/x86_64-pc-linux-gnu',
'-isystem',
'/usr/include/c++/11.2.0/backward',
'-isystem',
'/usr/local/include',
'-isystem',
'/usr/include',
'-isystem',
'/usr/lib/gcc/x86_64-pc-linux-gnu/11.2.0/include',
'-isystem',
'/usr/lib/gcc/x86_64-pc-linux-gnu/11.2.0/include-fixed',同理可以弄C语言
'-isystem',
'/usr/local/include',
'-isystem',
'/usr/include',
'-isystem',
'/usr/lib/gcc/x86_64-pc-linux-gnu/11.2.0/include',
'-isystem',
'/usr/lib/gcc/x86_64-pc-linux-gnu/11.2.0/include-fixed',
