I'd take one step back and ask the question: Why would anyone one a graphical system need to run a terminal emulator in order to get notified about new mail? What if someone uses all kinds of other applications (web browser, document editor, photo viewer, music player...), just not a terminal, why wouldn't they be notified? The right approach is not to fix whatever happens inside the terminal emulator, the right approach is to have a graphical indicator on the desktop.
I'd take one step back and ask the question: Why would anyone one a graphical system need to run a terminal emulator in order to get notified about new mail? What if someone uses all kinds of other applications (web browser, document editor, photo viewer, music player...), just not a terminal, why wouldn't they be notified? The right approach is not to fix whatever happens inside the terminal emulator, the right approach is to have a graphical indicator on the desktop.