nom: Building nom for no_std fails on dependency memchr

Hello there, I’m trying to build nom for a RISC-V target which will use no_std. But after adding it to my Cargo.toml rust complained that a dependency required std.

However looking at the previous issues, I found https://github.com/Geal/nom/issues/1370 and saw that there was a fix so I switched my dependency to point directly at github:

[dependencies.nom]
# version = "7.0.0"
git = "https://github.com/Geal/nom"
default-features = false
features = []

However this is still producing:

error[E0463]: can't find crate for `std`
  |
  = note: the `riscv32imac-unknown-none-elf` target may not support the standard library
  = note: `std` is required by `memchr` because it does not declare `#![no_std]`
  = help: consider building the standard library from source with `cargo build -Zbuild-std`

error: aborting due to previous error

For more information about this error, try `rustc --explain E0463`.
error: could not compile `memchr`

Looking at the nom Cargo.toml features, it seems like turning off all default features (like I’m doing above) should turn off std in all deps. And it did help, as I fixed the error I was getting in the issue above but I now get an error for memchr.

Any ideas why setting default-features = false wouldn’t do the trick for memchr?