diff --git a/ChangeLog b/ChangeLog
index 45f0743903..5a2fb9afc4 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,10 @@
+Tue Jul 15 21:58:20 2008  Nobuyoshi Nakada  <nobu@ruby-lang.org>
+
+	* ext/tk/{,tkutil/}extconf.rb: ruby/ruby.h no longer needs to be
+	  checked.
+
+	* ext/tk/{tcltklib.c,tkutil/tkutil.c}: check macros for each headers.
+
 Tue Jul 15 21:45:41 2008  Akinori MUSHA  <knu@iDaemons.org>
 
 	* ext/tk/extconf.rb, ext/tk/tcltklib.c, ext/tk/tkutil/tkutil.c: Do
diff --git a/ext/tk/extconf.rb b/ext/tk/extconf.rb
index ec0a12eac2..be3781251e 100644
--- a/ext/tk/extconf.rb
+++ b/ext/tk/extconf.rb
@@ -5,8 +5,6 @@ require 'mkmf'
 is_win32 = (/mswin|mingw|cygwin|bccwin|wince/ =~ RUBY_PLATFORM)
 #is_macosx = (/darwin/ =~ RUBY_PLATFORM)
 
-have_header("ruby/signal.h")
-have_header("ruby/encoding.h")
 have_func("ruby_native_thread_p", "ruby.h")
 have_func("rb_errinfo", "ruby.h")
 have_func("rb_safe_level", "ruby.h")
diff --git a/ext/tk/tcltklib.c b/ext/tk/tcltklib.c
index db31846e61..00a3256a82 100644
--- a/ext/tk/tcltklib.c
+++ b/ext/tk/tcltklib.c
@@ -10,12 +10,13 @@
 
 #ifdef HAVE_RUBY_SIGNAL_H
 #include "ruby/signal.h"
+#else
+#include "rubysig.h"
+#endif
 #ifdef HAVE_RUBY_ENCODING_H
 #include "ruby/encoding.h"
 #endif
-#else
-/* #include "ruby.h" */
-#include "rubysig.h"
+#ifndef HAVE_RUBY_RUBY_H
 #include "version.h"
 #endif
 
diff --git a/ext/tk/tkutil/extconf.rb b/ext/tk/tkutil/extconf.rb
index ed5de0ee64..34b91632eb 100644
--- a/ext/tk/tkutil/extconf.rb
+++ b/ext/tk/tkutil/extconf.rb
@@ -7,7 +7,6 @@ end
 
 if has_tk
   require 'mkmf'
-  have_header("ruby/ruby.h")
   have_func("rb_obj_instance_exec", "ruby.h")
   have_func("rb_sym_to_s", "ruby.h")
   have_func("strndup", "string.h")
diff --git a/ext/tk/tkutil/tkutil.c b/ext/tk/tkutil/tkutil.c
index 98197ee7b8..6f35e195df 100644
--- a/ext/tk/tkutil/tkutil.c
+++ b/ext/tk/tkutil/tkutil.c
@@ -13,11 +13,12 @@
 
 #ifdef HAVE_RUBY_SIGNAL_H
 #include "ruby/signal.h"
+#else
+#include "rubysig.h"
+#endif
+#ifdef HAVE_RUBY_ST_H
 #include "ruby/st.h"
 #else
-/* #include "ruby.h" */
-#include "rubysig.h"
-#include "version.h"
 #include "st.h"
 #endif