[ 64%] Building CXX object src/shogun/CMakeFiles/libshogun.dir/base/class_list.cpp.o
In file included from /home/eejya/shogun/src/shogun/kernel/normalizer/KernelNormalizer.h:16:0,
                 from /home/eejya/shogun/src/shogun/transfer/multitask/MultitaskKernelMaskNormalizer.h:16,
                 from /home/eejya/shogun/src/shogun/base/class_list.cpp:18:
/home/eejya/shogun/src/shogun/kernel/Kernel.h: In member function ‘float64_t shogun::CKernel::kernel(int32_t, int32_t)’:
/home/eejya/shogun/src/shogun/kernel/Kernel.h:213:21: error: invalid use of incomplete type ‘class shogun::CKernelNormalizer’
    return normalizer->normalize(compute(idx_a, idx_b), idx_a, idx_b);
                     ^
In file included from /home/eejya/shogun/src/shogun/kernel/normalizer/KernelNormalizer.h:16:0,
                 from /home/eejya/shogun/src/shogun/transfer/multitask/MultitaskKernelMaskNormalizer.h:16,
                 from /home/eejya/shogun/src/shogun/base/class_list.cpp:18:
/home/eejya/shogun/src/shogun/kernel/Kernel.h:35:8: error: forward declaration of ‘class shogun::CKernelNormalizer’
  class CKernelNormalizer;
        ^
make[2]: *** [src/shogun/CMakeFiles/libshogun.dir/base/class_list.cpp.o] Error 1
make[1]: *** [src/shogun/CMakeFiles/libshogun.dir/all] Error 2
make: *** [all] Error 2