diff --git a/lang/mono/Makefile b/lang/mono/Makefile
index 471b970c5cc..e44fcf3843f 100644
--- a/lang/mono/Makefile
+++ b/lang/mono/Makefile
@@ -1,6 +1,6 @@
-# $OpenBSD: Makefile,v 1.1.1.1 2008/10/15 13:34:10 robert Exp $
+# $OpenBSD: Makefile,v 1.2 2008/10/15 21:33:25 robert Exp $
 
-ONLY_FOR_ARCHS=	i386
+ONLY_FOR_ARCHS=	amd64 i386
 
 COMMENT=	cross platform, open source .NET developement framework
 
@@ -26,7 +26,7 @@ WANTLIB=	c glib-2.0 gmodule-2.0 gthread-2.0 intl \
 MASTER_SITES=	ftp://ftp.novell.com/pub/mono/sources/mono/
 EXTRACT_SUFX=	.tar.bz2
 
-#USE_LIBTOOL=	Yes
+USE_LIBTOOL=	Yes
 USE_GMAKE=	Yes
 
 MODULES=	converters/libiconv
diff --git a/lang/mono/patches/patch-mono_metadata_class_c b/lang/mono/patches/patch-mono_metadata_class_c
new file mode 100644
index 00000000000..27fb178103b
--- /dev/null
+++ b/lang/mono/patches/patch-mono_metadata_class_c
@@ -0,0 +1,15 @@
+$OpenBSD: patch-mono_metadata_class_c,v 1.1 2008/10/15 21:33:25 robert Exp $
+--- mono/metadata/class.c.orig	Wed Oct 15 22:15:14 2008
++++ mono/metadata/class.c	Wed Oct 15 22:39:45 2008
+@@ -7445,7 +7445,10 @@ mono_generic_class_is_generic_type_definition (MonoGen
+ gboolean
+ mono_class_generic_sharing_enabled (MonoClass *class)
+ {
+-#if defined(__i386__) || defined(__x86_64__)
++#if (defined(__NetBSD__) || defined(__OpenBSD__)) && defined(__x86_64__)
++/* https://bugzilla.novell.com/show_bug.cgi?id=434457 */
++	static gboolean supported = FALSE;
++#elif defined(__i386__) || defined(__x86_64__)
+ 	static gboolean supported = TRUE;
+ #else
+ 	/* Not supported by the JIT backends */
diff --git a/lang/mono/patches/patch-mono_mini_mini-amd64_h b/lang/mono/patches/patch-mono_mini_mini-amd64_h
index 66da06a22e0..f875e8c9d77 100644
--- a/lang/mono/patches/patch-mono_mini_mini-amd64_h
+++ b/lang/mono/patches/patch-mono_mini_mini-amd64_h
@@ -1,6 +1,6 @@
-$OpenBSD: patch-mono_mini_mini-amd64_h,v 1.1.1.1 2008/10/15 13:34:10 robert Exp $
---- mono/mini/mini-amd64.h.orig	Tue Oct 14 19:41:26 2008
-+++ mono/mini/mini-amd64.h	Tue Oct 14 19:48:56 2008
+$OpenBSD: patch-mono_mini_mini-amd64_h,v 1.2 2008/10/15 21:33:25 robert Exp $
+--- mono/mini/mini-amd64.h.orig	Tue Sep  2 17:42:54 2008
++++ mono/mini/mini-amd64.h	Wed Oct 15 22:07:39 2008
 @@ -217,7 +217,7 @@ typedef struct {
   */
  #define MONO_ARCH_VARARG_ICALLS 1
@@ -10,3 +10,12 @@ $OpenBSD: patch-mono_mini_mini-amd64_h,v 1.1.1.1 2008/10/15 13:34:10 robert Exp
  
  #define MONO_ARCH_USE_SIGACTION 1
  
+@@ -229,7 +229,7 @@ typedef struct {
+ 
+ #endif /* PLATFORM_WIN32 */
+ 
+-#ifdef __FreeBSD__
++#if defined(__FreeBSD__) || defined(__OpenBSD__)
+ 
+ #define REG_RAX 7
+ #define REG_RCX 4