Cannot compile with FFLD_HOGPYRAMID_EXTRA_FEATURES enabled

[manisoftwartist]

On enabling the above flag, the build fails with the message

In static member function ‘static void FFLD::HOGPyramid::Hog(const FFLD::JPEGImage&, FFLD::HOGPyramid::Level&, int, int, int)’:
ffldv2/HOGPyramid.cpp:319:44: error: ‘xm’ was not declared in this scope
    const int lbp = (static_cast<int>(linem[xm * depth + (depth > 1)] >= g)     ) |