Require CMake 3.12 because we want to use hwloc_ROOT to let users configure find_package.

Author: insertinterestingnamehere

Diff for: CMakeLists.txt

@@ -1,8 +1,4 @@
-if(CMAKE_VERSION VERSION_LESS "3.12.0")
-  cmake_minimum_required(VERSION 3.2)
-else()
-  cmake_minimum_required(VERSION 3.2...3.31)
-endif()
+cmake_minimum_required(VERSION 3.12...3.31)
 
 set(CMAKE_C_STANDARD 11)
 set(BUILD_SHARED_LIBS ON CACHE BOOL "Build using shared libraries.")