cc是unix中的c语言编译器，很多makefile也是用的cc，那在linux下是怎样的呢
答案就是。。在linux下cc==gcc
➜ makefile which cc
/usr/bin/cc
➜ makefile ll /usr/bin/cc
lrwxrwxrwx 1 root root 20 5月 4 2016 /usr/bin/cc -> /etc/alternatives/cc
➜ makefile ll /etc/alternatives/cc
lrwxrwxrwx 1 root root 12 5月 4 2016 /etc/alternatives/cc -> /usr/bin/gcc
