prelink: Disable on Darwin

https://hydra.nixos.org/build/60439488

A tool that works on ELF files only isn't probably that useful on
Darwin.

pkgs/development/tools/misc/prelink/default.nix

···
     homepage = http://people.redhat.com/jakub/prelink/;
     license = "GPL";
     description = "ELF prelinking utility to speed up dynamic linking";
-    platforms = stdenv.lib.platforms.all;
+    platforms = stdenv.lib.platforms.linux;
   };
 }