I can’t tell for sure, but it looks like a Lenovo y510p. Or at least it looks very similar to the one I owned back in the day.

There was a vent in the hinge, and these things would absolutely cook themselves with the lid closed

You don’t. In C everything gets referenced by a symbol during the link stage of compilation. Libraries ultimately get treated like your source code during compilation and all items land in a symbol table. Two items with the same name result in a link failure and compilation aborts. So a library and a program with main is no bueno.

When Linux loads an executable they basically look at the program’s symbol table and search for “main” then start executing at that point

Windows behaves mostly the same way, as does MacOS. Most RTOS’s have their own special way of doing things, bare metal you’re at the mercy of your CPU vendor. The C standard specifies that “main” is the special symbol we all just happen to use