安装nginx时会遇到错误提示gcc: command not found，需要先安装gcc
在centos7上安装成功。
# yum group list
# yum group install "Development Tools" 或 # sudo yum group install "Development Tools"
查看是否安装成功
$ whereis gcc gcc: /usr/bin/gcc /usr/lib/gcc /usr/libexec/gcc /usr/share/man/man1/gcc.1.gz