Enable the pager dependency on OSX, fixes build

Dependencies

• [2] 6DOXSHWG Cleanup, and version bump
• [3] 2K7JLB4Z No pager on Windows
• [4] TPEH2XNB 1.0.0-alpha.28, with Tokio 1.0
• [5] SAGSYAPX Various version bumps
• [6] YX3VCEOM Version bump
• [7] I52XSRUH Massive cleanup, and simplification
• [8] G734WNM6 flake.nix: use crate2nix
• [9] ZHABNS3S Canonicalize all paths
• [10] Q45QHPO4 Feedback on network stuff
• [11] R6LAMLHW Manual fix of Cargo.nix (to work around OSX's less)
• [12] LYTVEPH3 Avoid cloning into an existing path
• [13] OJZWJUF2 MUCH faster `pijul add -r`
• [*] SXEYMYF7 Fixing the bad changes in history (unfortunately, by rebooting).

Change contents

• replacement in pijul/Cargo.toml at line 82
  [3.310]→[3.97:146](∅→∅)
  − [target.'cfg(target_os = "linux")'.dependencies]
  [3.310]

  [3.344]
  + [target.'cfg(unix)'.dependencies]
• replacement in Cargo.nix at line 3761
  [3.79777]→[2.3133:3202](∅→∅)
  − target = { target, features }: (target."os" == "linux");
  [3.79777]

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