Spc_Emu.cpp line 290:

    count = long (count * resampler.ratio()) & ~1;
    
    count -= resampler.skip_input( count );

Replace these lines with

    if ( sample_rate() != native_sample_rate )
    {
        count = long (count * resampler.ratio()) & ~1;
        count -= resampler.skip_input( count );
    }