CMake file for day3 examples

day3/examples/CMakeLists.txt

+cmake_minimum_required(VERSION 3.16)
+set(CMAKE_CXX_EXTENSIONS OFF)
+set(CMAKE_CXX_STANDARD 20)
+set(CMAKE_CXX_STANDARD_REQUIRED ON)
+set(CMAKE_EXPORT_COMPILE_COMMANDS ON)
+project(cxx2023_d1_examples CXX)
+
+
+FILE (GLOB sources ./ *.cc)
+foreach(source ${sources})
+    get_filename_component(withoutext "${source}" NAME_WE)
+    add_executable("${withoutext}" "${source}")
+endforeach()
+
+