在 Mac 上安装 PySide 的时候得到提示：
running install
running build
Python architecture is 64bit
error: Failed to find cmake. Please specify the path to cmake with --cmake parameter.
原因是没有安装 CMake。
去 https://cmake.org/download/ 下载了最新版，安装后发现并没有成功命令行安装。
打开 CMake ， Tools 里有一个选项为：How to install for Command Line Use.
One may add CMake to the PATH:
PATH="/Applications/CMake.app/Contents/bin":"$PATH"
Or, to install symlinks to '/usr/local/bin', run:
sudo "/Applications/CMake.app/Contents/bin/cmake-gui" --install
Or, to install symlinks to another directory, run:
sudo "/Applications/CMake.app/Contents/bin/cmake-gui" --install=/path/to/bin
可以装 PySide了。
