Fix test build on Mac

Makefile

@@ -70,6 +70,8 @@ $(BUILD_DIR)/test/%.o: test/%.c
 $(TEST_FILE): $(LIB_FILE) $(TEST_OBJS)
 ifeq ($(OS),Windows_NT)
 	$(CC) -o $@ $(TEST_OBJS) $(LIB_FILE) -lglew32 -lopengl32 -lSDL2 -lSDL2main -lm
+else ifeq ($(shell uname -s),Darwin)
+	$(CC) -o $@ $(TEST_OBJS) $(LIB_FILE) -framework OpenGL -lGLEW -lSDL2 -lSDL2main -lm -lpthread
 else
 	$(CC) -o $@ $(TEST_OBJS) $(LIB_FILE) -lGLEW -lGL -lSDL2 -lSDL2main -lm -lpthread
 endif

README.md

@@ -19,7 +19,7 @@ project under the `test` directory as well, demonstrating usage of the library.
 - [Godot add-on](https://github.com/Brawmario/libsm64-godot)
 - [Game Maker 8 extension](https://github.com/headshot2017/libsm64-gm8)
 
-## Building on Linux
+## Building on Mac and Linux
 
 - Ensure python3 is installed.
 - Ensure the SDL2 and GLEW libraries are installed if you're building the test program (on Ubuntu: libsdl2-dev, libglew-dev).

test/gl20/gl20_renderer.c

@@ -1,5 +1,6 @@
 #include "gl20_renderer.h"
 
+#include <OpenGL/gl.h>
 #include <stdio.h>
 
 #include "../../src/libsm64.h"