Manual fix of Cargo.nix (to work around OSX's less)

Dependencies

• [2] YX3VCEOM Version bump
• [3] I52XSRUH Massive cleanup, and simplification
• [4] G734WNM6 flake.nix: use crate2nix
• [5] SAGSYAPX Various version bumps

Change contents

• replacement in Cargo.nix at line 3846
  [3.79777]→[2.212:271](∅→∅)
  − target = { target, features }: target."linux";
  [3.79777]

  [3.79777]
  + target = { target, features }: target."unix";