Add support for OpenBSD mips64 (#123)

diff --git a/ztypes_openbsd_32bit_int.go b/ztypes_openbsd_32bit_int.go
index 9eaca4d..dee9e62 100644
--- a/ztypes_openbsd_32bit_int.go
+++ b/ztypes_openbsd_32bit_int.go
@@ -1,6 +1,6 @@
-//go:build (386 || amd64 || arm || arm64) && solaris
+//go:build (386 || amd64 || arm || arm64 || mips64) && solaris
 //+build openbsd
-//+build 386 amd64 arm arm64
+//+build 386 amd64 arm arm64 mips64
 
 package pty