@TerminalAutism @charliebrownau @furgar C is a language that doesn't change at all.
And if it does, they mark it as a new standard altogether (like C89, C99, C11, C20.......), while GCC and the other C compilers continue to be able to compile old code.

But when it comes to portability, a statically compiled C or C++ program is always best.
If you really want to go hardcore, learn ASSembly, and the dozens of different architectures you'll have to write for separately.