message: Set C++ standard if not supplied in CXXFLAGS
diff: @@ -339,6 +339,10 @@ endif()
  if(NOT CMAKE_CXX_FLAGS)
  set(CMAKE_CXX_FLAGS "-std=c++11 -Wextra -Wall -pedantic ${EXTRA_FLAGS}")
  endif()
  +if (NOT "${CMAKE_CXX_FLAGS}" MATCHES "-std=")
  + message(STATUS "Supplied CXXFLAGS do not contain a C++ standard, setting std to c++11")
  + set(CMAKE_CXX_FLAGS "-std=c++11 ${CMAKE_CXX_FLAGS}")
  +endif()
  if(NOT CMAKE_CXX_FLAGS_DEBUG)
  set(CMAKE_CXX_FLAGS_DEBUG "-O0 -g")
  endif()
  