YDL 3.0 : where is the module n_hdlc ?

[Charles Trois]

When trying to install the Speedtouch modem, the log complains about not
finding the  module n_hdlc.

Indeed, it does not appear in xconfig nor in the config file.

But the source is there: /usr/src/linux-2.4/drivers/char/n_hdlc.c, and there
is a text about it in /usr/src/linux-2.4/Documentation/Configure.help.

What can be done to install this module?

Thanks for any suggestions.

Charles.