$OpenBSD: patch-modules_core_include_opencv2_core_operations_hpp,v 1.1.1.1 2019/03/22 20:39:06 rsadowski Exp $
All to build on sparc64 at least.
Index: modules/core/include/opencv2/core/operations.hpp
--- modules/core/include/opencv2/core/operations.hpp.orig
+++ modules/core/include/opencv2/core/operations.hpp
@@ -65,7 +65,7 @@
   #elif __GNUC__*10 + __GNUC_MINOR__ >= 42
 
     #if !(defined WIN32 || defined _WIN32) && (defined __i486__ || defined __i586__ || \
-        defined __i686__ || defined __MMX__ || defined __SSE__  || defined __ppc__) || \
+        defined __i686__ || defined __MMX__ || defined __SSE__  || defined __ppc__ || defined _GLIBCXX_ATOMIC_BUILTINS) || \
         defined _STLPORT_MAJOR || defined _LIBCPP_VERSION || \
         defined __EMSCRIPTEN__
 
