Use C++ 14 standard. Update minimum CMake version to 3.1.

Author: psyhtest

loadgen/CMakeLists.txt

@@ -1,4 +1,4 @@
-cmake_minimum_required(VERSION 3.0)
+cmake_minimum_required(VERSION 3.1)
 
 project(mlperf_loadgen)
 
@@ -7,9 +7,11 @@ set(mlperf_loadgen_VERSION_MAJOR 0)
 set(mlperf_loadgen_VERSION_MINOR 5)
 message("mlperf_loadgen v${mlperf_loadgen_VERSION_MAJOR}.${mlperf_loadgen_VERSION_MINOR}")
 
-# Set build options.
+# Set build options. NB: CXX_STANDARD is supported since CMake 3.1.
 set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -O2 -W -Wall")
-message(STATUS "Using compiler flags: ${CMAKE_CXX_FLAGS}")
+message(STATUS "Using C++ compiler flags: ${CMAKE_CXX_FLAGS}")
+set(CMAKE_CXX_STANDARD "14")
+message(STATUS "Using C++ standard: ${CMAKE_CXX_STANDARD}")
 message(STATUS "Using static linker flags: ${CMAKE_STATIC_LINKER_FLAGS}")
 message(STATUS "Using shared linker flags: ${CMAKE_SHARED_LINKER_FLAGS}")