Lib/lib-tk/FixTk.py

import sys, os, _tkinter
ver = str(_tkinter.TCL_VERSION)
for t in "tcl", "tk":
    v = os.path.join(sys.prefix, "tcl", t+ver)
    if os.path.exists(os.path.join(v, "tclIndex")):
        os.environ[t.upper() + "_LIBRARY"] = v