OpenBSD needs this tar invocation as well.

Author: 3405691582

utils/build-script-impl

@@ -3208,7 +3208,7 @@ function build_and_test_installable_package() {
               call tar -c -z -f "${package_for_host}" "${TOOLCHAIN_PREFIX/#\/}"
         else
             # BSD tar doesn't support --owner/--group.
-            if [[ "$(uname -s)" == "Darwin" || "$(uname -s)" == "FreeBSD" ]] ; then
+            if [[ "$(uname -s)" == "Darwin" || "$(uname -s)" == "FreeBSD" || "$(uname -s)" == "OpenBSD" ]] ; then
                 with_pushd "${host_install_destdir}" \
                     tar -c -z -f "${package_for_host}" "${host_install_prefix/#\/}"
             else