Rust's libstd for example uses environ when using the `envs` builder
method for spawning processes, and therefore relibc cannot simply assume
environ will always point to the internal relibc env var Vec.

Most shared object in linux have their initialization in a separate
.init_array section. but glibc does not have the same behavour. Instead
the initialization is part of crt0. which (as it seams to me) run after
.init_array section. As such, this patch move IO initialization to
separate function that is marked as .init_array member and then the crt0
call this function only if init_array was never invoked (as in
statically linked binaries).

I didn't think it'd be this useful first, but thank god for `cargo fix --edition`!

Huge thanks to @xTibor for both discovering that this was still an issue, and also providing information with how to fix it

Turns out, it's just redox not having a NULL pointer here. Linux does.