Once you've built this easy way out I fear it will turn into a crutch that stops new, pure rust apps from being written. Do you really want a C library in Redox?
There is tons of C software out there that depends on libc that is never going to be rewritten in Rust. Also think about interpreted languages like Python, Ruby, etc. I imagine they all depend on libc. The only real way for Redox to gain adoption is through cross platform compatibility.
Does the rust compiler depend on libc?
Presumably. Rust programs certainly do.
The compiler does. Rust programs don't inherently depend on libc; it's libstd that does. Build without the standard library, no libc required.
Do you want Redox unable to run 90% of the world's existing systems software?