Index: gcc/d/d-port.cc
--- gcc/d/d-port.cc.orig
+++ gcc/d/d-port.cc
@@ -169,3 +169,10 @@ Port::valcpy (void *buffer, uint64_t value, d_size_t s
       gcc_unreachable ();
     }
 }
+
+#if defined(__OpenBSD__) && defined(__LP64__)
+void Port::valcpy(void *dst, unsigned long val, size_t size)
+{
+    valcpy(dst, (uint64_t)val, size);
+}
+#endif
