Fail to compile phobos

[JJDuck via Digitalmars-d-learn]

I tried to compile phobos according to the last paragraph in this 
page:
http://dlang.org/dmd-linux.html

but this is the error I have
fatal: Not a git repository (or any of the parent directories): 
.git


I dont know what happened, i have tried for a few days.

BTW, should I place my dmd2 folder at ~ or /usr/local/share. 
which will have less prblem in installing and maintaining?

Thanks