> main.cpp:8:19: fatal error: variant: No such file or directory

> compilation terminated.

> Makefile:167: recipe for target 'main.o' failed

> make: *** [main.o] Error 1

安装g ++ - 7; 例如，如果ubuntu

sudo add-apt-repository ppa:ubuntu-toolchain-r/test -y 

sudo apt-get update 

sudo apt-get install g++-7

add-apt-repository: command not found

解决方法

apt-get install software-properties-common python-software-properties