diff --git a/ruby-1.8.x-RHASH_SIZE-def.patch b/ruby-1.8.x-RHASH_SIZE-def.patch
deleted file mode 100644
index e7c119a..0000000
--- a/ruby-1.8.x-RHASH_SIZE-def.patch
+++ /dev/null
@@ -1,16 +0,0 @@
-Index: ruby_1_8/ruby.h
-===================================================================
---- ruby_1_8/ruby.h	(revision 13310)
-+++ ruby_1_8/ruby.h	(revision 13311)
-@@ -374,6 +374,11 @@
-     int iter_lev;
-     VALUE ifnone;
- };
-+#define RHASH_TBL(h) (RHASH(h)->tbl)
-+#define RHASH_ITER_LEV(h) (RHASH(h)->iter_lev)
-+#define RHASH_IFNONE(h) (RHASH(h)->ifnone)
-+#define RHASH_SIZE(h) (RHASH(h)->tbl->num_entries)
-+#define RHASH_EMPTY_P(h) (RHASH_SIZE(h) == 0)
- 
- struct RFile {
-     struct RBasic basic;
diff --git a/ruby-1.8.x-RHASH_SIZE-rb_hash_lookup-def.patch b/ruby-1.8.x-RHASH_SIZE-rb_hash_lookup-def.patch
new file mode 100644
index 0000000..503a6b4
--- /dev/null
+++ b/ruby-1.8.x-RHASH_SIZE-rb_hash_lookup-def.patch
@@ -0,0 +1,65 @@
+Sat Apr 19 18:42:04 2008  Akinori MUSHA  <knu@iDaemons.org>
+
+	* intern.h, hash.c (rb_hash_lookup): New internal function to
+	  check if a key exists in a hash, ignoring #default; backported
+	  from 1.9.
+
+Thu Aug 30 08:24:18 2007  Tanaka Akira  <akr@fsij.org>
+
+	* ruby.h (RHASH_TBL): defined for compatibility to 1.9.
+	* (RHASH_ITER_LEV): ditto.
+	* (RHASH_IFNONE): ditto.
+	* (RHASH_SIZE): ditto.
+	* (RHASH_EMPTY_P): ditto.
+
+Index: ruby_1_8/ruby.h
+===================================================================
+--- ruby_1_8/ruby.h	(revision 13310)
++++ ruby_1_8/ruby.h	(revision 13311)
+@@ -374,6 +374,11 @@
+     int iter_lev;
+     VALUE ifnone;
+ };
++#define RHASH_TBL(h) (RHASH(h)->tbl)
++#define RHASH_ITER_LEV(h) (RHASH(h)->iter_lev)
++#define RHASH_IFNONE(h) (RHASH(h)->ifnone)
++#define RHASH_SIZE(h) (RHASH(h)->tbl->num_entries)
++#define RHASH_EMPTY_P(h) (RHASH_SIZE(h) == 0)
+ 
+ struct RFile {
+     struct RBasic basic;
+Index: ruby_1_8/hash.c
+===================================================================
+--- ruby_1_8/hash.c	(revision 16077)
++++ ruby_1_8/hash.c	(revision 16078)
+@@ -454,6 +454,18 @@
+     return val;
+ }
+ 
++VALUE
++rb_hash_lookup(hash, key)
++    VALUE hash, key;
++{
++    VALUE val;
++
++    if (!st_lookup(RHASH(hash)->tbl, key, &val)) {
++	return Qnil; /* without Hash#default */
++    }
++    return val;
++}
++
+ /*
+  *  call-seq:
+  *     hsh.fetch(key [, default] )       => obj
+Index: ruby_1_8/intern.h
+===================================================================
+--- ruby_1_8/intern.h	(revision 16077)
++++ ruby_1_8/intern.h	(revision 16078)
+@@ -270,6 +270,7 @@
+ VALUE rb_hash_new _((void));
+ VALUE rb_hash_freeze _((VALUE));
+ VALUE rb_hash_aref _((VALUE, VALUE));
++VALUE rb_hash_lookup _((VALUE, VALUE));
+ VALUE rb_hash_aset _((VALUE, VALUE, VALUE));
+ VALUE rb_hash_delete_if _((VALUE));
+ VALUE rb_hash_delete _((VALUE,VALUE));
diff --git a/ruby.spec b/ruby.spec
index 1e4f1f7..d6fadb8 100644
--- a/ruby.spec
+++ b/ruby.spec
@@ -18,7 +18,7 @@
 
 Name:		ruby
 Version:	%{rubyver}%{?dotpatchlevel}
-Release:	3%{?dist}
+Release:	3.1%{?dist}
 License:	Ruby or GPLv2
 URL:		http://www.ruby-lang.org/
 BuildRoot:	%{_tmppath}/%{name}-%{version}-%{release}-root-%(%{__id_u} -n)
@@ -83,8 +83,11 @@ Patch34:	ruby-1.8.6-simplify-openssl-digest.patch
 Patch35:	ruby_1_8_7-gc-open4_096segv.patch
 #
 # Patch36, 37: needed to use the head of ext/tk directory of ruby_1_8 branch head
-# Patch36: taken from ruby_1_8 branch
-Patch36:        ruby-1.8.x-RHASH_SIZE-def.patch
+# Patch36: taken from ruby_1_8 branch, RHASH_SIZE definition is needed
+# for ruby_1_8 head ext/tk
+# With this change, rb_hash_lookup becomes also needed for rubygem-nokogiri
+# (bug 592936)
+Patch36:        ruby-1.8.x-RHASH_SIZE-rb_hash_lookup-def.patch
 # Patch37: flatten(level) feature is in >= 1.8.7, reverting
 Patch37:        ruby-1.8.x-ext_tk-flatten-level-revert.patch
 # From ruby_1_8 branch: bz 530407
@@ -634,6 +637,10 @@ rm -rf $RPM_BUILD_ROOT
 %{_emacs_sitestartdir}/ruby-mode-init.el
 
 %changelog
+* Mon May 17 2010 Mamoru Tasaka <mtasaka@ioa.s.u-tokyo.ac.jp> - 1.8.6.399-4
+- Patch36 (ruby-1.8.x-RHASH_SIZE-rb_hash_lookup-def.patch)
+  also backport rb_hash_lookup definition (bug 592936)
+
 * Thu May 13 2010 Mamoru Tasaka <mtasaka@ioa.s.u-tokyo.ac.jp> - 1.8.6.399-3
 - ruby-1.8.x-null-class-must-be-Qnil.patch (bug 530407)
 - Recreate some patches using upstream svn when available, and