Patch by Stanislav Maslovski <stanislav.maslovski@gmail.com>.
See http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=488501

--- tk8.5-8.5.8.orig/generic/tkPort.h
+++ tk8.5-8.5.8/generic/tkPort.h
@@ -29,7 +29,7 @@
 #   if defined(MAC_OSX_TK)
 #	include "tkMacOSXPort.h"
 #   else
-#	include "tkUnixPort.h"
+#	include "../unix/tkUnixPort.h"
 #   endif
 #endif