Install toolchain
mkdir ~/esp32
cd ~/esp32
wget https://dl.espressif.com/dl/xtensa-esp32-elf-osx-1.22.0-80-g6c4433a-5.2.0.tar.gz
tar xvfz xtensa-esp32-elf-osx-1.22.0-80-g6c4433a-5.2.0.tar.gz
rm *.gz
Add toolchain to your path
vi ~/.profile
export PATH=$PATH:$HOME/esp32/xtensa-esp32-elf/bin
Install ESP-IDF
cd ~/esp32
git clone -b v3.1.1 --recursive https://github.com/espressif/esp-idf.git
Add IDF_PATH environment variable
vi ~/.profile
export IDF_PATH=~/esp32/esp-idf