Index: ext/tk/extconf.rb
===================================================================
--- ext/tk/extconf.rb.orig	2008-04-09 16:15:24.000000000 +0200
+++ ext/tk/extconf.rb	2008-06-21 04:29:14.717425749 +0200
@@ -95,7 +95,7 @@ def check_tcltk_version(version)
 end
 
 def find_tcl(tcllib, stubs, version, *opt_paths)
-  default_paths = ["/usr/local/lib", "/usr/pkg/lib", "/usr/lib"]
+  default_paths = ["/usr/local/lib64", "/usr/local/lib", "/usr/pkg/lib64", "/usr/pkg/lib", "/usr/lib64", "/usr/lib"]
   default_paths << "/Tcl/lib"  # default for ActiveTcl
 
   if (paths = opt_paths.compact).empty?
@@ -138,7 +138,7 @@ def find_tcl(tcllib, stubs, version, *op
 end
 
 def find_tk(tklib, stubs, version, *opt_paths)
-  default_paths = ["/usr/local/lib", "/usr/pkg/lib", "/usr/lib"]
+  default_paths = ["/usr/local/lib64", "/usr/local/lib", "/usr/pkg/lib64", "/usr/pkg/lib", "/usr/lib64", "/usr/lib"]
   default_paths << "/Tcl/lib"  # default for ActiveTcl
 
   if (paths = opt_paths.compact).empty?
@@ -182,7 +182,7 @@ end
 
 def find_X11(*opt_paths)
   default_paths = 
-    [ "/usr/X11/lib", "/usr/lib/X11", "/usr/X11R6/lib", "/usr/openwin/lib" ]
+    [ "/usr/X11/lib64", "/usr/X11/lib", "/usr/lib64/X11", "/usr/lib/X11", "/usr/X11R6/lib64", "/usr/X11R6/lib", "/usr/openwin/lib64", "/usr/openwin/lib" ]
   paths = opt_paths.compact.concat(default_paths)
   st = find_library("X11", "XOpenDisplay", *paths)
   unless st