Building GCC From Source

I needed a baseline bash script to build GCC from source.
Of course if your machine is AMD64 you can just use compiled binaries from various repositories such as AUR, Conda, Spack, etc.
Nevertheless, before cross compiling GCC, you should know how you can build it normally for your own machine.
To avoid editing this post often, I created a public Gist for the bash script. You can find it here.