--- configure.orig	2008-04-17 17:14:08.000000000 +0200
+++ configure	2010-12-09 09:27:23.108864895 +0100
@@ -3427,6 +3428,7 @@
 #define _POSIX_PTHREAD_SEMANTICS 1
 EOF
 
+TCL_SRC_DIR=${prefix}/include/tcl${TCLVERSION}
 
 	    SHLIB_CFLAGS="-KPIC"
 
