message: core:ppc Fix compile issue with Eigen
diff: #include "opencv2/core/cvdef.h"
  +#ifndef SKIP_INCLUDES
  +# include <assert.h>
  +#endif
  +
  //! @addtogroup core_utils_vsx
  //! @{
  #if CV_VSX
  @@ -520,6 +524,27 @@ VSX_IMPL_CONV_EVEN_2_4(vec_float4, vec_udword2, vec_ctf, vec_ctfo)
  VSX_IMPL_CONV_EVEN_2_4(vec_int4, vec_double2, vec_cts, vec_ctso)
  VSX_IMPL_CONV_EVEN_2_4(vec_uint4, vec_double2, vec_ctu, vec_ctuo)
  +// Only for Eigen!
  +/*
  + * changing behavior of conversion intrinsics for gcc has effect on Eigen
  + * so we redfine old behavior again only on gcc, clang
  +*/
  +#if !defined(__clang__) || __clang_major__ > 4
  + // ignoring second arg since Eigen only truncates toward zero
  +# define VSX_IMPL_CONV_2VARIANT(rt, rg, fnm, fn2) \
  + VSX_FINLINE(rt) fnm(const rg& a, int only_truncate) \
  + { \
  + assert(only_truncate == 0); \
  + (void)only_truncate; \
  + return fn2(a); \
  + }
  + VSX_IMPL_CONV_2VARIANT(vec_int4, vec_float4, vec_cts, vec_cts)
  + VSX_IMPL_CONV_2VARIANT(vec_float4, vec_int4, vec_ctf, vec_ctf)
  + // define vec_cts for converting double precision to signed doubleword
  + // which isn't combitable with xlc but its okay since Eigen only use it for gcc
  + VSX_IMPL_CONV_2VARIANT(vec_dword2, vec_double2, vec_cts, vec_ctsl)
  +#endif // Eigen
  +
  #endif // Common GCC, CLANG compatibility
  /*
  