Describe the bug
The gcc used for pkgsMusl.pkgsStatic.stdenv fails to build on x86_64-linux, due to a faulty bintools setup, as pointed out by Sandro here: #112096 (comment).

I think the reason for this is that the binutils hostPlatform is different from the targetPlatform (host is dynamic musl, target is static) but the configs are both x86_64-unknown-linux-musl. So our package definitions expect the resulting bintools to have a x86_64-unknown-linux-musl targetPrefix, but they do not because the autotools configure script only sees matching host/target configs, so it produces unprefixed ld, as, etc binaries.

To Reproduce
nix-build '<nixpkgs>' -A pkgsMusl.pkgsStatic.stdenv

Notify maintainers
Nixpkgs cross maintainers: @matthewbauer @Ericson2314

Metadata

• system: "x86_64-linux"
• host os: Linux 5.4.87, NixOS, 21.03pre268206.536fe36e23a (Okapi)
• multi-user?: yes
• sandbox: yes
• version: nix-env (Nix) 2.3.10
• channels(root): "nixos-21.03pre268206.536fe36e23a"
• nixpkgs: /nix/var/nix/profiles/per-user/root/channels/nixos

Maintainer information:

# a list of nixpkgs attributes affected by the problem
attribute:
  - binutils
  - gcc
# a list of nixos modules affected by the problem
module: