macOS 更新后导致 sdk 丢失问题

在 macOS 更新后，CLion 可能会出现如下错误

CMake Warning at /Applications/CLion.app/Contents/bin/cmake/mac/share/cmake-3.15/Modules/Platform/Darwin-Initialize.cmake:131 (message):
  Ignoring CMAKE_OSX_SYSROOT value:

   /Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX12.1.sdk

  because the directory does not exist.

这时候，只需要删除 cmake-build-debug 或者对应的目录，然后 reload cmake 就行了