Note that this is no-std no-alloc target, with all the limitations that leads to.

You could add alloc with a custom global allocator, but I don't even know what high perf global allocator you could use that wouldn't need libc. Jemalloc and mimalloc are out. Some embedded allocators would work (but those are rarely high performance, instead being optimised for small code and data footprints).

That said, with enough effort (quite a lot!) it would be possible to add support for alloc and std without libc on Linux specifically (since it has a stable syscall ABI).

What might be more realistic though is looking at relibc (a rust implementation of libc, made for Redox OS but from what I read it also supports Linux). But I haven't tried it and I don't know the state (or goal) of it.