The libraries OpenGL and GLUT are part of the standard Xcode installation.

Download the files, including the Makefiles, to a folder, just like on Linux.

Make sure that the extension .txt was not added to the Makefile, or delete it if it was.

In both .cc files, replace
#include <GL/glut.h> //Linux
with
#include <GLUT/glut.h> //MacOS

In the Makefile, replace the Linux libraries
LIB_LIST = -lGL -lglut -lGLU
with the MacOS ones
LIB_LIST = -framework GLUT -framework OpenGL -framework Cocoa

Open a terminal, go to the homework folder, and compile with the command make, just as you would on Linux. To execute the program you'll probably need to type ./gradient.

Before submission, replace the included header file everywhere with the original.