Fix build falure using xcode new build system (#3647)

Signed-off-by: Guoyu Wang <wanggy@outlook.com>

Co-authored-by: Chun-Wei Chen <jacky82226@gmail.com>

CMakeLists.txt

@@ -54,7 +54,7 @@ if(ONNX_USE_PROTOBUF_SHARED_LIBS)
     add_definitions(-DPROTOBUF_USE_DLLS)
   endif()
   set(Protobuf_USE_STATIC_LIBS OFF)
-else() 
+else()
   set(Protobuf_USE_STATIC_LIBS ON)
 endif()
 
@@ -360,6 +360,7 @@ list(REMOVE_ITEM __tmp_srcs ${onnx_gtests_src})
 list(APPEND ONNX_SRCS ${__tmp_srcs})
 
 add_library(onnx_proto ${ONNX_PROTO_SRCS} ${ONNX_PROTO_HDRS})
+add_dependencies(onnx_proto gen_onnx_operators_proto gen_onnx_data_proto)
 target_include_directories(onnx_proto PUBLIC
   $<BUILD_INTERFACE:${CMAKE_CURRENT_BINARY_DIR}>
   $<INSTALL_INTERFACE:include>