diff -Naur grpc-1.39.0-original/tools/distrib/python/grpcio_tools/protoc_lib_deps.py grpc-1.39.0/tools/distrib/python/grpcio_tools/protoc_lib_deps.py
--- grpc-1.39.0-original/tools/distrib/python/grpcio_tools/protoc_lib_deps.py	2021-07-20 18:39:39.000000000 -0400
+++ grpc-1.39.0/tools/distrib/python/grpcio_tools/protoc_lib_deps.py	2021-07-23 14:46:07.887714469 -0400
@@ -14,10 +14,9 @@
 # limitations under the License.
 
 # AUTO-GENERATED BY make_grpcio_tools.py!
-CC_FILES=['google/protobuf/compiler/zip_writer.cc', 'google/protobuf/compiler/subprocess.cc', 'google/protobuf/compiler/ruby/ruby_generator.cc', 'google/protobuf/compiler/python/python_generator.cc', 'google/protobuf/compiler/plugin.pb.cc', 'google/protobuf/compiler/plugin.cc', 'google/protobuf/compiler/php/php_generator.cc', 'google/protobuf/compiler/objectivec/objectivec_primitive_field.cc', 'google/protobuf/compiler/objectivec/objectivec_oneof.cc', 'google/protobuf/compiler/objectivec/objectivec_message_field.cc', 'google/protobuf/compiler/objectivec/objectivec_message.cc', 'google/protobuf/compiler/objectivec/objectivec_map_field.cc', 'google/protobuf/compiler/objectivec/objectivec_helpers.cc', 'google/protobuf/compiler/objectivec/objectivec_generator.cc', 'google/protobuf/compiler/objectivec/objectivec_file.cc', 'google/protobuf/compiler/objectivec/objectivec_field.cc', 'google/protobuf/compiler/objectivec/objectivec_extension.cc', 'google/protobuf/compiler/objectivec/objectivec_enum_field.cc', 'google/protobuf/compiler/objectivec/objectivec_enum.cc', 'google/protobuf/compiler/js/well_known_types_embed.cc', 'google/protobuf/compiler/js/js_generator.cc', 'google/protobuf/compiler/java/java_string_field_lite.cc', 'google/protobuf/compiler/java/java_string_field.cc', 'google/protobuf/compiler/java/java_shared_code_generator.cc', 'google/protobuf/compiler/java/java_service.cc', 'google/protobuf/compiler/java/java_primitive_field_lite.cc', 'google/protobuf/compiler/java/java_primitive_field.cc', 'google/protobuf/compiler/java/java_name_resolver.cc', 'google/protobuf/compiler/java/java_message_lite.cc', 'google/protobuf/compiler/java/java_message_field_lite.cc', 'google/protobuf/compiler/java/java_message_field.cc', 'google/protobuf/compiler/java/java_message_builder_lite.cc', 'google/protobuf/compiler/java/java_message_builder.cc', 'google/protobuf/compiler/java/java_message.cc', 'google/protobuf/compiler/java/java_map_field_lite.cc', 'google/protobuf/compiler/java/java_map_field.cc', 'google/protobuf/compiler/java/java_helpers.cc', 'google/protobuf/compiler/java/java_generator_factory.cc', 'google/protobuf/compiler/java/java_generator.cc', 'google/protobuf/compiler/java/java_file.cc', 'google/protobuf/compiler/java/java_field.cc', 'google/protobuf/compiler/java/java_extension_lite.cc', 'google/protobuf/compiler/java/java_extension.cc', 'google/protobuf/compiler/java/java_enum_lite.cc', 'google/protobuf/compiler/java/java_enum_field_lite.cc', 'google/protobuf/compiler/java/java_enum_field.cc', 'google/protobuf/compiler/java/java_enum.cc', 'google/protobuf/compiler/java/java_doc_comment.cc', 'google/protobuf/compiler/java/java_context.cc', 'google/protobuf/compiler/csharp/csharp_wrapper_field.cc', 'google/protobuf/compiler/csharp/csharp_source_generator_base.cc', 'google/protobuf/compiler/csharp/csharp_repeated_primitive_field.cc', 'google/protobuf/compiler/csharp/csharp_repeated_message_field.cc', 'google/protobuf/compiler/csharp/csharp_repeated_enum_field.cc', 'google/protobuf/compiler/csharp/csharp_reflection_class.cc', 'google/protobuf/compiler/csharp/csharp_primitive_field.cc', 'google/protobuf/compiler/csharp/csharp_message_field.cc', 'google/protobuf/compiler/csharp/csharp_message.cc', 'google/protobuf/compiler/csharp/csharp_map_field.cc', 'google/protobuf/compiler/csharp/csharp_helpers.cc', 'google/protobuf/compiler/csharp/csharp_generator.cc', 'google/protobuf/compiler/csharp/csharp_field_base.cc', 'google/protobuf/compiler/csharp/csharp_enum_field.cc', 'google/protobuf/compiler/csharp/csharp_enum.cc', 'google/protobuf/compiler/csharp/csharp_doc_comment.cc', 'google/protobuf/compiler/cpp/cpp_string_field.cc', 'google/protobuf/compiler/cpp/cpp_service.cc', 'google/protobuf/compiler/cpp/cpp_primitive_field.cc', 'google/protobuf/compiler/cpp/cpp_padding_optimizer.cc', 'google/protobuf/compiler/cpp/cpp_message_field.cc', 'google/protobuf/compiler/cpp/cpp_message.cc', 'google/protobuf/compiler/cpp/cpp_map_field.cc', 'google/protobuf/compiler/cpp/cpp_helpers.cc', 'google/protobuf/compiler/cpp/cpp_generator.cc', 'google/protobuf/compiler/cpp/cpp_file.cc', 'google/protobuf/compiler/cpp/cpp_field.cc', 'google/protobuf/compiler/cpp/cpp_extension.cc', 'google/protobuf/compiler/cpp/cpp_enum_field.cc', 'google/protobuf/compiler/cpp/cpp_enum.cc', 'google/protobuf/compiler/command_line_interface.cc', 'google/protobuf/compiler/code_generator.cc', 'google/protobuf/wrappers.pb.cc', 'google/protobuf/wire_format.cc', 'google/protobuf/util/type_resolver_util.cc', 'google/protobuf/util/time_util.cc', 'google/protobuf/util/message_differencer.cc', 'google/protobuf/util/json_util.cc', 'google/protobuf/util/internal/utility.cc', 'google/protobuf/util/internal/type_info_test_helper.cc', 'google/protobuf/util/internal/type_info.cc', 'google/protobuf/util/internal/protostream_objectwriter.cc', 'google/protobuf/util/internal/protostream_objectsource.cc', 'google/protobuf/util/internal/proto_writer.cc', 'google/protobuf/util/internal/object_writer.cc', 'google/protobuf/util/internal/json_stream_parser.cc', 'google/protobuf/util/internal/json_objectwriter.cc', 'google/protobuf/util/internal/json_escaping.cc', 'google/protobuf/util/internal/field_mask_utility.cc', 'google/protobuf/util/internal/error_listener.cc', 'google/protobuf/util/internal/default_value_objectwriter.cc', 'google/protobuf/util/internal/datapiece.cc', 'google/protobuf/util/field_mask_util.cc', 'google/protobuf/util/field_comparator.cc', 'google/protobuf/util/delimited_message_util.cc', 'google/protobuf/unknown_field_set.cc', 'google/protobuf/type.pb.cc', 'google/protobuf/timestamp.pb.cc', 'google/protobuf/text_format.cc', 'google/protobuf/stubs/substitute.cc', 'google/protobuf/struct.pb.cc', 'google/protobuf/source_context.pb.cc', 'google/protobuf/service.cc', 'google/protobuf/reflection_ops.cc', 'google/protobuf/message.cc', 'google/protobuf/map_field.cc', 'google/protobuf/io/tokenizer.cc', 'google/protobuf/io/printer.cc', 'google/protobuf/io/gzip_stream.cc', 'google/protobuf/generated_message_table_driven.cc', 'google/protobuf/generated_message_reflection.cc', 'google/protobuf/field_mask.pb.cc', 'google/protobuf/extension_set_heavy.cc', 'google/protobuf/empty.pb.cc', 'google/protobuf/dynamic_message.cc', 'google/protobuf/duration.pb.cc', 'google/protobuf/descriptor_database.cc', 'google/protobuf/descriptor.pb.cc', 'google/protobuf/descriptor.cc', 'google/protobuf/compiler/parser.cc', 'google/protobuf/compiler/importer.cc', 'google/protobuf/api.pb.cc', 'google/protobuf/any.pb.cc', 'google/protobuf/any.cc', 'google/protobuf/wire_format_lite.cc', 'google/protobuf/stubs/time.cc', 'google/protobuf/stubs/strutil.cc', 'google/protobuf/stubs/structurally_valid.cc', 'google/protobuf/stubs/stringprintf.cc', 'google/protobuf/stubs/stringpiece.cc', 'google/protobuf/stubs/statusor.cc', 'google/protobuf/stubs/status.cc', 'google/protobuf/stubs/int128.cc', 'google/protobuf/stubs/common.cc', 'google/protobuf/stubs/bytestream.cc', 'google/protobuf/repeated_field.cc', 'google/protobuf/parse_context.cc', 'google/protobuf/message_lite.cc', 'google/protobuf/map.cc', 'google/protobuf/io/zero_copy_stream_impl_lite.cc', 'google/protobuf/io/zero_copy_stream_impl.cc', 'google/protobuf/io/zero_copy_stream.cc', 'google/protobuf/io/strtod.cc', 'google/protobuf/io/io_win32.cc', 'google/protobuf/io/coded_stream.cc', 'google/protobuf/implicit_weak_message.cc', 'google/protobuf/generated_message_util.cc', 'google/protobuf/generated_message_table_driven_lite.cc', 'google/protobuf/generated_enum_util.cc', 'google/protobuf/extension_set.cc', 'google/protobuf/arenastring.cc', 'google/protobuf/arena.cc', 'google/protobuf/any_lite.cc']
+# Then, modified by hand to build with an external system protobuf installation.
+CC_FILES=[]
 PROTO_FILES=['google/protobuf/wrappers.proto', 'google/protobuf/type.proto', 'google/protobuf/timestamp.proto', 'google/protobuf/struct.proto', 'google/protobuf/source_context.proto', 'google/protobuf/field_mask.proto', 'google/protobuf/empty.proto', 'google/protobuf/duration.proto', 'google/protobuf/descriptor.proto', 'google/protobuf/compiler/plugin.proto', 'google/protobuf/api.proto', 'google/protobuf/any.proto']
 
-CC_INCLUDE='third_party/protobuf/src'
-PROTO_INCLUDE='third_party/protobuf/src'
-
-PROTOBUF_SUBMODULE_VERSION="436bd7880e458532901c58f4d9d1ea23fa7edd52"
+CC_INCLUDE='/usr/include'
+PROTO_INCLUDE='/usr/include'