CMake version 3.12 and policy

CMakeLists.txt

-cmake_minimum_required(VERSION 3.8 FATAL_ERROR)
+cmake_minimum_required(VERSION 3.12 FATAL_ERROR)
+
+# CMP0074: find_package() uses <PackageName>_ROOT variables
+cmake_policy(SET CMP0074 NEW)
+
 project(NPDet 
   VERSION 0.5.0
   LANGUAGES CXX)

src/dd4pod/CMakeLists.txt

-cmake_minimum_required(VERSION 3.3 FATAL_ERROR)
+cmake_minimum_required(VERSION 3.12 FATAL_ERROR)
+
+# CMP0074: find_package() uses <PackageName>_ROOT variables
+cmake_policy(SET CMP0074 NEW)
 
 include(GNUInstallDirs)
 

src/detectors/CMakeLists.txt

-cmake_minimum_required(VERSION 3.3 FATAL_ERROR)
+cmake_minimum_required(VERSION 3.12 FATAL_ERROR)
+
+# CMP0074: find_package() uses <PackageName>_ROOT variables
+cmake_policy(SET CMP0074 NEW)
 
 set(CMAKE_BUILD_TYPE Debug)
 # see https://rix0r.nl/blog/2015/08/13/cmake-guide/

src/plugins/CMakeLists.txt

-cmake_minimum_required(VERSION 3.3 FATAL_ERROR)
+cmake_minimum_required(VERSION 3.12 FATAL_ERROR)
+
+# CMP0074: find_package() uses <PackageName>_ROOT variables
+cmake_policy(SET CMP0074 NEW)
 
 # see https://rix0r.nl/blog/2015/08/13/cmake-guide/
 # Must use GNUInstallDirs to install libraries into correct

src/tools/CMakeLists.txt

-cmake_minimum_required(VERSION 3.3 FATAL_ERROR)
+cmake_minimum_required(VERSION 3.12 FATAL_ERROR)
+
+# CMP0074: find_package() uses <PackageName>_ROOT variables
+cmake_policy(SET CMP0074 NEW)
 
 include(GNUInstallDirs)
 find_package(fmt REQUIRED)