linux升级cmake
如果出现如下报错，就应该升级cmake了！
CMake Error at CMakeLists.txt:1 (cmake_minimum_required):
CMake 3.1 or higher is required. You are running version 2.8.12.2
-- Configuring incomplete, errors occurred!
官网
可以下载各个版本的cmake: https://cmake.org/files/
升级
1.下载cmake，这里选择cmake-3.12.4，当然可以选择更新的版本：
进入https://cmake.org/files/v3.12/
选择cmake-3.12.4.tar.gz
2.解压后进入文件夹进行编译编译
./bootstrap
make
sudo make install3.查看版本
cmake --version打印如下，说明安装成功了！
cmake version 3.12.4
安装完后，发现make会出报错如下：
CMake Error: Could not find CMAKE_ROOT !!!
CMake has most likely not been installed correctly.
Modules directory not found in
/usr/local/bin
CMake Error: Error executing cmake::LoadCache(). Aborting.
hash -r问题3
-- Could NOT find OpenSSL, try to set the path to OpenSSL root folder in the system variable OPENSSL_ROOT_DIR (missing: OPENSSL_CRYPTO_LIBRARY OPENSSL_INCLUDE_DIR)
sudo yum install openssl-devel