Making tmux find ssh agent on reattach

.zsh func psg

fixssh() {
  for key in SSH_AUTH_SOCK SSH_CONNECTION SSH_CLIENT; do
    if (tmux show-environment | grep "^${key}" > /dev/null); then
      value=`tmux show-environment | grep "^${key}" | sed -e "s/^[A-Z_]*=//"`
      export ${key}="${value}"
    fi
  done
}

.zshrc

preexec() {
  if [[ -n $TMUX && ! -S "$SSH_AUTH_SOCK" ]]; then
     fixssh
  fi
}