张量流是否定义USE_GEMM_FOR_CONV

Question

conv_ops.cc中卷积运算的实现涉及USE_GEMM_FOR_CONV

#if !defined(USE_GEMM_FOR_CONV)
TF_CALL_half(REGISTER_CPU);
TF_CALL_float(REGISTER_CPU);
TF_CALL_double(REGISTER_CPU);
#endif  // USE_GEMM_FOR_CONV

如何确定程序是否定义了USE_GEMM_FOR_CONV？