On macOS 10.14 i observe lately in my system.log that nix-daemon crashes due to the apple changes on fork since 10.13. The following message comes in regurarly:

nix-daemon[38220]: objc[38220]: +[__NSPlaceholderArray initialize] may have been in progress in another thread when fork() was called. We cannot safely call it or ignore it in the fork() child process. Crashing instead. Set a breakpoint on objc_initializeAfterForkError to debug.

Related discussion in nixpkgs for other packages: NixOS/nixpkgs#44160
Related info: http://sealiesoftware.com/blog/archive/2017/6/5/Objective-C_and_fork_in_macOS_1013.html

Do we need to update the SDK dependency for our buildsystem?