The exec-path-from-shell package is a must-have for the OS X Emacs user. Before I found it, I could never get the search path for Emacs configured correctly. Once I installed it, all those problems disappeared and I haven’t thought about them since. Really; if you’re using Emacs on a Mac, you need this.
(Via Emacs – Irreal)
Here’s the recipe from my config:
(when (memq window-system '(mac ns))
Since I use the same config on multiple OSes the opening line makes sure it only installs on a OS X/macOS host.