OS X has added some paths that are apparently not allowed to be linked.
Michael Tsai has the only writeup on this that I have been able to find:
https://mjtsai.com/blog/2016/07/22/xcode-8-illegal-hard-links-prevent-cloning/
Basically any file ending in .app/Contents/PkgInfo and .app/Contents/Resources/*.lproj cannot be hard linked.
See also NixOS/nixpkgs#25819
OS X has added some paths that are apparently not allowed to be linked.
Michael Tsai has the only writeup on this that I have been able to find:
https://mjtsai.com/blog/2016/07/22/xcode-8-illegal-hard-links-prevent-cloning/
Basically any file ending in
.app/Contents/PkgInfoand.app/Contents/Resources/*.lprojcannot be hard linked.See also NixOS/nixpkgs#25819