[Xotcl] Bug: configure step chooses wrong tclsh

[jim at jam.sessionsnet.org]

Hi, 

When configuring xotcl to build with a tcl which is not the system tcl,
the configure step assumes the tclsh in the $PATH, which is a wrong 
assumption.

The right assumption would be to choose the tclsh located in the tclConfig.sh.

Doing this would ensure the builder will get the tclsh which is in the
installation of tcl he/she specified.

-Jim