I build the EDKII firmware without any problems in Debian GNU/Linux 7.5 (wheezy).
What is the error message for ./gitsetup.py? Also what Linux version are you using?
INFO: Running: svn commit --depth empty --message Add svn:externals .
svn: warning: The depth of this commit is 'empty', but copied directories will regardless be committed with depth 'infinity'. You must remove unwanted children of those directories in a separate commit.
Committed revision 1.
This is just a warning, you can ignore and continue.