Implemented PEP 405 (Python virtual environments).
diff --git a/Lib/tkinter/_fix.py b/Lib/tkinter/_fix.py
index 5a69d89..5f32d25 100644
--- a/Lib/tkinter/_fix.py
+++ b/Lib/tkinter/_fix.py
@@ -46,10 +46,10 @@
             s = "\\" + s[3:]
         return s
 
-prefix = os.path.join(sys.prefix,"tcl")
+prefix = os.path.join(sys.base_prefix,"tcl")
 if not os.path.exists(prefix):
     # devdir/../tcltk/lib
-    prefix = os.path.join(sys.prefix, os.path.pardir, "tcltk", "lib")
+    prefix = os.path.join(sys.base_prefix, os.path.pardir, "tcltk", "lib")
     prefix = os.path.abspath(prefix)
 # if this does not exist, no further search is needed
 if os.path.exists(prefix):