Using gpg-agent with emacs under OS X

load-gpg-agent-environment.el

;; read gpg-agent environment
(defun read-env-line (line)
  "read a env line and post to environment"
  (let ((key-value-pair (split-string line "=" t)))
    (setenv (car key-value-pair) (car (last key-value-pair))))
  )
(defvar gpg-agent-info-file)
(setq gpg-agent-info-file (concat (getenv "HOME") "/.gpg-agent-info"))
(when
    (file-exists-p gpg-agent-info-file)
  (with-temp-buffer
    (progn
      (insert-file-contents gpg-agent-info-file)
      (mapc 'read-env-line (split-string (buffer-string) "\n" t)))
    ))