解决mac OS xcrun error, missing xcrun

在mac OS安装ta-lib时，遇到xcrun error。

xcrun: error: invalid active developer path (/Library/Developer/CommandLineTools), missing xcrun at: /Library/Developer/CommandLineTools/usr/bin/xcrun
      error: command '/usr/bin/clang' failed with exit code 1
      [end of output]

  note: This error originates from a subprocess, and is likely not a problem with pip.
  ERROR: Failed building wheel for ta-lib

执行命令

$ xcode-select --install

会跳出如下窗口，点击安装。

即解决missing xcrun的问题。