From the v18 trace file attached earlier we see this:
27592 execve("/usr/bin/svn", ["/usr/bin/svn", "--non-interactive", "diff", "-r", "HEAD", "/space/gbarron/work/mo-trunk/sof"...], .......
Maybe you need to specify the diff command to ignore any user options?:
27592 execve("/usr/bin/svn", ["/usr/bin/svn", "--non-interactive", "diff", "--diff-cmd", "/usr/bin/diff" "-r", "HEAD", "/space/gbarron/work/mo-trunk/sof"...], .......