When --build_dir is provided use it and do not pollute source directory
which even can be mounted over network or read-only.
Signed-off-by: NAndy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: NBrendan Higgins <brendanhiggins@google.com>
Tested-by: NBrendan Higgins <brendanhiggins@google.com>
Signed-off-by: NShuah Khan <skhan@linuxfoundation.org>