update code.

Author: xuhancn

src/BuildOnWindows.cmake

@@ -43,6 +43,7 @@ if(BUILD_SEPARATE_OPS)
       ${sycl_lib}
       SHARED
       SYCL_SOURCES ${sycl_src})
+    target_compile_definitions(${sycl_lib} PRIVATE TORCH_XPU_BUILD_MAIN_LIB)
     target_link_libraries(torch_xpu_ops PUBLIC ${sycl_lib})
     list(APPEND TORCH_XPU_OPS_LIBRARIES ${sycl_lib})