已修复.运行brew reinstall gettext时，命令实际上给出了答案:

Fixed. When running brew reinstall gettext, command actually give the answer:

If you need to have gettext first in your PATH run:
  echo 'export PATH="/usr/local/opt/gettext/bin:$PATH"' >> ~/.zshrc

仅在打开新的zsh提示符时才触发导出，但PATH尚未更新，并且在重新打开新窗口时有效.

Export is only triggered when opening a new zsh prompt, PATH was not updated yet and worked when I re-openned a new window.