SDL2: https://www.libsdl.org/download-2.0.php
just download the appropriate development library for your compiler and place it in "./SDL2/"

libogg: https://xiph.org/downloads/ (libogg)
download the libogg .zip file and unzip it in "./libogg/", then build the library as a framework, and include it in the xcode proj

libvorbis: https://xiph.org/downloads/ (libvorbis)
download the libogg .zip file and unzip it in "./libvorbis/", then build the library as a framework, and include it in the xcode proj

libtheora: https://xiph.org/downloads/ (libtheora)
download the libogg .zip file and unzip it in "./libtheora/", then build the library as a framework, and include it in the xcode proj