Index: src/third_party/mozjs/mozilla-release/build/moz.configure/toolchain.configure
--- src/third_party/mozjs/mozilla-release/build/moz.configure/toolchain.configure.orig
+++ src/third_party/mozjs/mozilla-release/build/moz.configure/toolchain.configure
@@ -2291,7 +2291,7 @@ set_define("_LIBCPP_HIDE_FROM_ABI", libcxx_override_vi
 @depends(target, build_environment)
 def visibility_flags(target, env):
     if target.os != "WINNT":
-        if target.kernel == "Darwin":
+        if target.kernel == 'Darwin' or target.kernel == 'OpenBSD':
             return ("-fvisibility=hidden", "-fvisibility-inlines-hidden")
         return (
             "-I%s/system_wrappers" % os.path.join(env.dist),
