Patch by Stanislav Maslovski <stanislav.maslovski@gmail.com>.
See http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=488491

--- tcl8.5-8.5.11.orig/generic/tclPort.h
+++ tcl8.5-8.5.11/generic/tclPort.h
@@ -22,7 +22,7 @@
 #endif
 #include "tcl.h"
 #if !defined(_WIN32)
-#   include "tclUnixPort.h"
+#   include "../unix/tclUnixPort.h"
 #endif
 
 #if defined(__CYGWIN__)