使用命令：
`g++ -print-prog-name=cc1plus` -v结果：
忽略不存在的目录“/usr/lib/gcc/x86_64-redhat-linux/4.8.5/include-fixed”
忽略不存在的目录“/usr/lib/gcc/x86_64-redhat-linux/4.8.5/../../../../x86_64-redhat-linux/include”
#include "..." 搜索从这里开始：
#include <...> 搜索从这里开始：
/usr/lib/gcc/x86_64-redhat-linux/4.8.5/../../../../include/c++/4.8.5
/usr/lib/gcc/x86\_64-redhat-linux/4.8.5/../../../../include/c++/4.8.5/x86_64-redhat-linux
/usr/lib/gcc/x86_64-redhat-linux/4.8.5/../../../../include/c++/4.8.5/backward
/usr/lib/gcc/x86_64-redhat-linux/4.8.5/include
/usr/local/include
/usr/include
搜索列表结束。