message: CreateMutex workaround for xsmm
diff: #include "base/util/lookup.h"
  #include "tile/stripe/stripe.h"
  +#if defined(_WIN32)
  +// As of 2019-08-01, libxsmm doesn't compile on Windows if UNICODE is defined, since it passes
  +// an ANSI string to CreateMutexW(). So we rewrite it.
  +#undef CreateMutex
  +#define CreateMutex CreateMutexA
  +#endif
  +
  // libxsmm
  #include "libxsmm_source.h" // NOLINT
  