The C++ version in the CMakeLists for direct download of the A-LOAM library is 11, as follows:

cmake_minimum_required(VERSION 2.8.3)
project(aloam_velodyne)

set(CMAKE_BUILD_TYPE "Release")
set(CMAKE_CXX_FLAGS "-std=c++11")
set(CMAKE_CXX_FLAGS_RELEASE "-O3 -Wall -g")

But Ceres 2.0 and above requires C++14 compiler, so you just need to change the C++ compiler to 14

cmake_minimum_required(VERSION 2.8.3)
project(aloam_velodyne)

set(CMAKE_BUILD_TYPE "Release")
set(CMAKE_CXX_FLAGS "-std=c++14")
set(CMAKE_CXX_FLAGS_RELEASE "-O3 -Wall -g")

‘