Suggestion to make the path to `i386-elf-gcc` configurable in the Makefile

Hello,

First of all, thank you very much for sharing this great OS tutorial repository!

I encountered an issue where the Makefile contains a hardcoded path for the i386-elf-gcc compiler:

CC=/usr/local/i386elfgcc/bin/i386-elf-gcc

Since the installation path for i386-elf-gcc may differ depending on the user's environment, it would be helpful if this path were configurable or if the Makefile could allow using the system's PATH to find the compiler automatically.

For example, allowing setting the compiler via an environment variable or using just i386-elf-gcc if it's available in the PATH would improve usability.

Thank you for your consideration!

Best regards,

@yucchanneltv