After installing Xcode you’ll want to open up a terminal and ensure you have accepted the developer license:
$ sudo xcodebuild -license
$ sudo xcode-select --install
$ /usr/bin/ruby -e "$(curl -fsSL https://raw.githubusercontent.com/Homebrew/install/master/install)"
$ brew update
Add to .bash_profile
# Homebrew
export PATH=/usr/local/bin:$PATH
$ brew install librtlsdr
$ https://github.com/merbanan/rtl_433
$ cd rtl_433
$ mkdir build && cd $_
$ cmake ../ && make
$ ./src/rtl_433 -h