Compatibility with CMake < 3.5 was removed from CMake 4.

Index: CMakeLists.txt
--- CMakeLists.txt.orig
+++ CMakeLists.txt
@@ -1,4 +1,4 @@
-cmake_minimum_required(VERSION 3.0)
+cmake_minimum_required(VERSION 3.5)
 
 # option() honors normal variables.
 # see: https://cmake.org/cmake/help/git-stage/policy/CMP0077.html