::pkg::create is a utility procedure that is part of the
standard Tcl library. It is used to create an appropriate
package ifneeded command for a given package specification.
It can be used to construct a pkgIndex.tcl file for use with
the package mechanism.
This parameter specifies a binary library that must be loaded
with the load command.
filespec is a list with two elements. The first element is
the name of the file to load. The second, optional element is a
list of commands supplied by loading that file. If the list of
procedures is empty or omitted, ::pkg::create will set up
the library for direct loading (see pkg_mkIndex). Any number
of -load parameters may be specified.