Arch Linux: core won't compile

Created by: Ploppz

Following the instructions for Arch Linux, I get lots of these compiler errors when I try to makepkg -si in libc/packages/arch/newlib:

   Compiling core v0.0.0 (file:///home/ploppz/code/redox/libc/packages/arch/newlib/src/rust/src/libcore)
error[E0204]: the trait `Copy` may not be implemented for this type
  --> /home/ploppz/code/redox/libc/packages/arch/newlib/src/rust/src/libcore/num/flt2dec/decoder.rs:24:10
   |
24 | #[derive(Copy, Clone, Debug, PartialEq, Eq)]
   |          ^^^^
...
27 |     pub mant: u64,
   |     ------------- this field does not implement `Copy`

I tried both latest nightly and latest stable. (by rustup default)