make build error

[cheny110]

Hi, when I cloned and tried to build this project following the README instruction, i encountered following error:

Makefile:39: *** YOU HAVE TO USE GIT TO DOWNLOAD THIS REPOSITORY. ABORTING..
or something like this:
fatal: not a git repository (or any of the parent directories): .git
CMake Error at src/lib/version/CMakeLists.txt:47 (message):
is not a git repository

It seems sub-modules in the directory don't contain git relevant information that required by making process.
How should i resolve such problem? Any advise or suggestions would be appreciated , thank you !