Function: _def_help
Class: gp_default
Section: default
C-Name: sd_help
Prototype:
Help:
Doc: name of the external help program which will be used from within
 \kbd{gp} when extended help is invoked, usually through a \kbd{??} or
 \kbd{???} request (see \secref{se:exthelp}), or \kbd{M-H} under readline (see
 \secref{se:readline}).

 The default value is the local of the \kbd{gphelp} script.
