Earlier quoted context omitted.
What is the roadmap on getting rid of the need for libc? Given how terrible libc is, I personally would make that a high priority, though I guess in Linux you can't even start up a process without libc (maybe that is a misunderstanding?), which makes the situation less clean, but at least you could get to a point where you never call back into it after entry into main.
Do you suggest they should use raw system calls? On most systems your options are either calling standard C functions or doing raw calls (not portable). Someone did start a C stdlib implementation in Rust, but it appears to be inactive: https://github.com/mahkoh/rlibc
You could have a dummy version that just calls out to libc, for compatibility with systems that you haven't finished porting to yet.