Update how we set SSH_AUTH_SOCK.

dotfiles/zshrc.d/gpg.zsh

@@ -20,13 +20,19 @@ fi
 # Inform gpg-agent of the current TTY for user prompts.
 export GPG_TTY="$(tty)"
 
-# Integrate with the SSH module.
+# Setup SSH agent support
 if grep '^enable-ssh-support' "$_gpg_agent_conf" &> /dev/null; then
   # Load required functions.
   autoload -Uz add-zsh-hook
 
-  # Override the ssh-agent environment file default path.
-  _ssh_agent_env="$_gpg_agent_env"
+  if test -z "$SSH_AUTH_SOCK" ; then
+    SSH_AUTH_SOCK="/run/user/$(id -u)/gnupg/S.gpg-agent.ssh"
+    if test -S "$SSH_AUTH_SOCK" ; then
+      export SSH_AUTH_SOCK
+    else
+      unset SSH_AUTH_SOCK
+    fi
+  fi
 
   # Updates the GPG-Agent TTY before every command since SSH does not set it.
   function _gpg-agent-update-tty {