How to use code for OV7670 on Arduino Uno
I am ComputerNerd. I read this post and realized the real problem and why I am having difficulty helping you. You are asking the wrong question. What you should be asking is "how do I compile it using GNU Make and Avr-Gcc on Windows?". Instead you are asking "how can I use this code in the Arduino IDE?".

The answer to what you should be asking is simple. Use what you already have. The Arduino IDE ships with Avr-gcc and (maybe) GNU Make. Just run the programs directly. Better yet download MinGW and compile GCC to target the AVR yourself.