chore(3p/nix): Remove some OS X specific defines

This project will be dropping OS X support until the core is simplified.

third_party/nix/src/libstore/optimise-store.cc

@@ -105,18 +105,6 @@ void LocalStore::optimisePath_(OptimiseStats& stats, const Path& path,
     throw SysError(format("getting attributes of path '%1%'") % path);
   }
 
-#if __APPLE__
-  /* HFS/macOS has some undocumented security feature disabling hardlinking for
-     special files within .app dirs. *.app/Contents/PkgInfo and
-     *.app/Contents/Resources/\*.lproj seem to be the only paths affected. See
-     https://github.com/NixOS/nix/issues/1443 for more discussion. */
-
-  if (std::regex_search(path, std::regex("\\.app/Contents/.+$"))) {
-    debug(format("'%1%' is not allowed to be linked in macOS") % path);
-    return;
-  }
-#endif
-
   if (S_ISDIR(st.st_mode)) {
     Strings names = readDirectoryIgnoringInodes(path, inodeHash);
     for (auto& i : names) {