diff --git a/ChangeLog b/ChangeLog
index e67f783f86..45f0743903 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,9 @@
+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
+	  not test ruby/ruby.h, which makes OS X's gcc pick the wrong
+	  header file from Ruby.framework.
+
 Tue Jul 15 21:31:26 2008  Akinori MUSHA  <knu@iDaemons.org>
 
 	* configure.in (--with-ruby-version): Add a new option to specify
diff --git a/ext/tk/extconf.rb b/ext/tk/extconf.rb
index 7762b2a060..ec0a12eac2 100644
--- a/ext/tk/extconf.rb
+++ b/ext/tk/extconf.rb
@@ -5,7 +5,7 @@ require 'mkmf'
 is_win32 = (/mswin|mingw|cygwin|bccwin|wince/ =~ RUBY_PLATFORM)
 #is_macosx = (/darwin/ =~ RUBY_PLATFORM)
 
-have_header("ruby/ruby.h")
+have_header("ruby/signal.h")
 have_header("ruby/encoding.h")
 have_func("ruby_native_thread_p", "ruby.h")
 have_func("rb_errinfo", "ruby.h")
diff --git a/ext/tk/tcltklib.c b/ext/tk/tcltklib.c
index 9e14fc4f89..db31846e61 100644
--- a/ext/tk/tcltklib.c
+++ b/ext/tk/tcltklib.c
@@ -8,8 +8,7 @@
 
 #include "ruby.h"
 
-#ifdef HAVE_RUBY_RUBY_H
-/* #include "ruby/ruby.h" */
+#ifdef HAVE_RUBY_SIGNAL_H
 #include "ruby/signal.h"
 #ifdef HAVE_RUBY_ENCODING_H
 #include "ruby/encoding.h"
diff --git a/ext/tk/tkutil/tkutil.c b/ext/tk/tkutil/tkutil.c
index fb07efbc03..98197ee7b8 100644
--- a/ext/tk/tkutil/tkutil.c
+++ b/ext/tk/tkutil/tkutil.c
@@ -11,8 +11,7 @@
 
 #include "ruby.h"
 
-#ifdef HAVE_RUBY_RUBY_H
-/* #include "ruby/ruby.h" */
+#ifdef HAVE_RUBY_SIGNAL_H
 #include "ruby/signal.h"
 #include "ruby/st.h"
 #else