Index: setupext.py
===================================================================
--- setupext.py	(revision 6281)
+++ setupext.py	(working copy)
@@ -942,7 +942,8 @@
     try:
         tcl_lib = tcl_vars.get("default", "TCL_LIB_SPEC")[1:-1].split()[0][2:]
         tcl_inc = tcl_vars.get("default", "TCL_INCLUDE_SPEC")[3:-1]
-        tk_lib = tk_vars.get("default", "TK_LIB_SPEC")[1:-1].split()[0][2:]
+        if tk_vars.get("default", "TK_LIB_SPEC")[1:-1].split():
+            tk_lib = tk_vars.get("default", "TK_LIB_SPEC")[1:-1].split()[0][2:]
         if tk_vars.has_option("default", "TK_INCLUDE_SPEC"):
             # On Ubuntu 8.04
             tk_inc = tk_vars.get("default", "TK_INCLUDE_SPEC")[3:-1]