message: Add `/D_USE_MATH_DEFINES` to host copt to fix windows builds.
diff: @@ -240,6 +240,7 @@ build:windows --copt=/w
  # Tensorflow uses M_* math constants that only get defined by MSVC headers if
  # _USE_MATH_DEFINES is defined.
  build:windows --copt=/D_USE_MATH_DEFINES
  +build:windows --host_copt=/D_USE_MATH_DEFINES
  # Default paths for TF_SYSTEM_LIBS
  build:linux --define=PREFIX=/usr
  