I have taken the package Itcl 3.4 in the folder /System/Library/Tcl/8.5/itcl3.4 from AS 8.5.8.1 for MacOSX and put it in the lib folder of my standalone application with an embedded Wish. After modifying the variable auto_path to my application's lib folder the command <package require Itcl> will result in an error complaining that there is no itcl.tcl in the known lib pathes.
I suggest to put the following line into the pkgIndex.tcl like in Linux teacup version of Itcl 3.4:
set ::env(ITCL_LIBRARY) $dir
Zbigniew Diaczyszyn