centos7.4 安装cmake could not find CMAKE_ROOT

cmake 的安装  

    ```

    cd /usr/local/

    tar -zxv -f cmake-3.13.0-rc2.tar.gz

    cd cmake-3.13.0-rc2

    ./configure

    make

    make install

CMake Error: Could not find CMAKE_ROOT !!!

   1中办法：执行命令

hash -r 

2种办法

    ./bootstrap --prefix=/usr

    gmake

    gmake install

    ```