--- ocaml-3.12.1/byterun/signals_machdep.h.orig	2015-03-13 11:34:46.335858998 +0000
+++ ocaml-3.12.1/byterun/signals_machdep.h	2015-03-13 11:12:03.915890556 +0000
@@ -18,7 +18,7 @@
 #ifndef CAML_SIGNALS_MACHDEP_H
 #define CAML_SIGNALS_MACHDEP_H
 
-#if defined(__GNUC__) && defined(__i386__)
+#if defined(__GNUC__) && (defined(__i386__) || (defined(__x86_64__) && !defined(__LP64__)))
 
 #define Read_and_clear(dst,src) \
   asm("xorl %0, %0; xchgl %0, %1" \
--- ocaml-3.12.1/otherlibs/num/bng.c.orig	2010-05-21 13:00:49.000000000 +0100
+++ ocaml-3.12.1/otherlibs/num/bng.c	2015-03-13 11:18:00.421882298 +0000
@@ -17,7 +17,7 @@
 #include "config.h"
 
 #if defined(__GNUC__) && BNG_ASM_LEVEL > 0
-#if defined(BNG_ARCH_ia32)
+#if defined(BNG_ARCH_ia32) || (defined(BNG_ARCH_amd64) && !defined(__LP64__))
 #include "bng_ia32.c"
 #elif defined(BNG_ARCH_amd64)
 #include "bng_amd64.c"