HPCC-12658 Enable c++11 support by default

Signed-off-by: Gavin Halliday <gavin.halliday@lexisnexis.com>

cmake_modules/commonSetup.cmake

@@ -260,6 +260,7 @@ IF ("${COMMONSETUP_DONE}" STREQUAL "")
           SET (CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -Wparentheses")
         endif ()
       endif ()
+      SET (CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -std=c++11")
       if (GENERATE_COVERAGE_INFO)
         message ("Build system with coverage.")
         SET (CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -fprofile-arcs -ftest-coverage")