I'm tried compiling a no-std executable that depends on ring to the x86_64-unknown-none target and got a linker error listing several "undefined references" like ring_core_0_17_5_ChaCha20_ctr32 and ring_core_0_17_5_bn_mul_mont.

I have tracked down the problem to these being symbols in the (pregenerated?) asm group. The build script does not produce the assembly files because none is not in the LINUX_ABI list. Adding "none" to this list fixes the linker error and produces a working binary. I have also tested that my program works (+) with the aarch64-unknown-none target. I'll submit a PR with that change.

(+) I'll eventually push the source code of my program to this draft rustls PR