Added steps for MacOS Ventura M-silicon support

[sapertuz]

for the code to compile on MacOS you should:

First, install the macOS command line tools:

$ xcode-select --install 

Install the LLVM OpenMP library.

$ brew install libomp llvm

Set the following environment variables:

$ export CC=/usr/bin/clang
$ export CXX=/usr/bin/clang++
$ export CPPFLAGS="$CPPFLAGS -Xpreprocessor -fopenmp"
$ export CFLAGS="$CFLAGS -I/opt/homebrew/opt/libomp/include"
$ export CXXFLAGS="$CXXFLAGS -I/opt/homebrew/opt/libomp/include"
$ export LDFLAGS="$LDFLAGS -Wl,-rpath,/opt/homebrew/opt/llvm/lib -L/opt/homebrew/opt/llvm/lib -lomp"

Feel free to add this to the readme. Thank you