diff --git a/OpenImageIO-1.1.3-SHA1_undef_ref.patch b/OpenImageIO-1.1.3-SHA1_undef_ref.patch
new file mode 100644
index 0000000..972895b
--- /dev/null
+++ b/OpenImageIO-1.1.3-SHA1_undef_ref.patch
@@ -0,0 +1,14 @@
+diff -Naur oiio-Release-1.1.3.orig/src/libutil/SHA1.cpp oiio-Release-1.1.3/src/libutil/SHA1.cpp
+--- oiio-Release-1.1.3.orig/src/libutil/SHA1.cpp	2013-01-09 19:13:37.000000000 -0600
++++ oiio-Release-1.1.3/src/libutil/SHA1.cpp	2013-01-15 07:53:27.479132623 -0600
+@@ -8,9 +8,9 @@
+ 
+ // If compiling with MFC, you might want to add #include "StdAfx.h"
+ 
++#include "SHA1.h"
+ #include "hash.h"
+ #include "dassert.h"
+-#include "SHA1.h"
+ 
+ #ifdef SHA1_UTILITY_FUNCTIONS
+ #define SHA1_MAX_FILE_BUFFER 8000
diff --git a/OpenImageIO.spec b/OpenImageIO.spec
index 3b5f7bb..ebac483 100644
--- a/OpenImageIO.spec
+++ b/OpenImageIO.spec
@@ -19,6 +19,8 @@ Source101:      FindTBB.cmake
 
 Patch0:         OpenImageIO-1.1.2-use_external_tbb.patch
 Patch2:         OpenImageIO-ppc.patch
+# https://github.com/OpenImageIO/oiio/issues/473
+Patch3:         OpenImageIO-1.1.3-SHA1_undef_ref.patch
 
 BuildRequires:  cmake txt2man
 BuildRequires:  qt4-devel
@@ -89,6 +91,7 @@ Development files for package %{name}
 %ifarch ppc ppc64
 %patch2 -p1 -b .ppc
 %endif
+%patch3 -p1 -b .sha1
 
 # Install FindTBB.cmake
 install %{SOURCE101} src/cmake/modules/