https://github.com/zlib-ng/minizip-ng/pull/657

From 3aa42e0520e4e7ffeae5a3def458c7ee0fefacb9 Mon Sep 17 00:00:00 2001
From: Sam James <sam@gentoo.org>
Date: Sat, 19 Nov 2022 03:09:34 +0000
Subject: [PATCH] Search system for GTest before downloading. #654

Distributions often do builds with no network access available
for both security reasons and also to ensure reproducibility.

This change tells CMake to query the system for a copy of gtest,
but if it's not available, it'll fall back to downloading via
FetchContent.
--- a/test/CMakeLists.txt
+++ b/test/CMakeLists.txt
@@ -2,6 +2,8 @@ cmake_minimum_required(VERSION 3.12)
 
 include(FetchContent)
 
+find_package(GTest)
+
 enable_language(CXX)
 
 if(NOT TARGET GTest::GTest)