第一次u安装使用Cmake时报错，如下：
CMake Error: CMake was unable to find a build program corresponding to "Unix Makefiles". CMAKE_MAKE_PROGRAM is not set. You probably need to select a different build tool.
CMake Error: CMAKE_C_COMPILER not set, after EnableLanguage
CMake Error: CMAKE_CXX_COMPILER not set, after EnableLanguage
-- Configuring incomplete, errors occurred!
原因：未安装make
解决方案：
ubuntu 18.04系统中输入命令 $sudo apt-get install make
安装完成后输入cmake .命令不再报错。