message: Update the instructions about macOS installation
diff: @@ -81,8 +81,9 @@ Get OpenCV from homebrew:
  ```shell script
  brew install opencv
  ```
  - You will also need a working C++ compiler and libclang, you can use the ones from XCode or install `llvm`
  - from brew. You most probably need to also check the item 6 of the troubleshooting below.
  + You will also need a working C++ compiler and libclang, you can install Command Line Tools (xcode-select
  + --install), XCode (from AppStore) or `llvm` (from Brew). You most probably need to also check the item 6 of the
  + troubleshooting below.
  ### Manual build
  @@ -137,12 +138,16 @@ You need to set up the following environment variables to point to the installed
  OS can't find `libclang.dylib` dynamic library because it resides in a non-standard path, set up
  the `DYLD_FALLBACK_LIBRARY_PATH` environment variable to point to the path where libclang.dylib can be
  - found, e.g. for Xcode:
  -
  + found, e.g. for Command Line Tools:
  ```
  export DYLD_FALLBACK_LIBRARY_PATH="$(xcode-select --print-path)/usr/lib/"
  ```
  + or XCode:
  + ```
  + export DYLD_FALLBACK_LIBRARY_PATH="$(xcode-select --print-path)/Toolchains/XcodeDefault.xctoolchain/usr/lib/"
  + ```
  +
  7. You're getting the panic: ```a `libclang` shared library is not loaded on this thread```.
  Enable the `clang-runtime` feature. The reason for the issue is that some crates (like `bindgen`) depend on
  