Standard C stops you. The C standard library is hardcoded to call the main function. Providing one's own ELF entry point also breaks libc initialization unless the exact same startfiles are used.

Freestanding C gets rid of the libc so that's not a problem.

Maybe you could also do some runtime linking trickery when dynamically linking libc?

The libc could easily add support for such a thing but I doubt they'd care enough to. They'd probably see it as adding complexity for zero gain.

I submitted an issue to the GCC bugzilla about renaming certain symbols generated by compiler.

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=113694

I don't know how to implement it and nobody else cared enough to.