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