今天讲一下NDK编译protobuf-3.12.0-rc2：

下载android-ndk-r13b-windows-x86_64.zip:https://dl.google.com/android/repository/android-ndk-r13b-windows-x86_64.zip?utm_source=androiddevtools&utm_medium=website,解压到：：C:/android/android-ndk-r13b

下载protobuf-3.12.0-rc2：https://github.com/protocolbuffers/protobuf/releases/,解压到：c:/protobuf-3.12.0-rc2

一。添加NDK环境变量：

我的NDK安装路径为：C:/android/android-ndk-r13b,因为在CMD下编译，要运行 ndk-build命令，所有要加2个系统环境变量：

cocos2d-x要的变量为：NDK_ROOT

ndk-build命令环境变量在Path中加：%NDK_ROOT%\build 

二.在c:/protobuf-3.12.0-rc2/src 建立make文件（文件名注意大小写）：

1.application.mk

APP_MODULES      := protobuf
APP_PLATFORM     := android-19
APP_ABI          := armeabi-v7a
APP_STL := c++_static
APP_OPTIM        := release

2.android.mk

LOCAL_PATH := $(call my-dir)include $(CLEAR_VARS)LOCAL_MODULE := protobuf
LOCAL_CFLAGS := -std=c++11 -fexceptions -frtti
LOCAL_MODULE_FILENAME := libprotobuf
LOCAL_SRC_FILES :=  google/protobuf/stubs/bytestream.cc                          \google/protobuf/stubs/bytestream.h                           \google/protobuf/stubs/common.cc                              \google/protobuf/stubs/hash.h                                 \google/protobuf/stubs/int128.cc                              \google/protobuf/stubs/int128.h                               \google/protobuf/io/io_win32.cc                               \google/protobuf/stubs/map_util.h                             \google/protobuf/stubs/mathutil.h                             \google/protobuf/stubs/status.cc                              \google/protobuf/stubs/status.h                               \google/protobuf/stubs/status_macros.h                        \google/protobuf/stubs/statusor.cc                            \google/protobuf/stubs/statusor.h                             \google/protobuf/stubs/stringpiece.cc                         \google/protobuf/stubs/stringpiece.h                          \google/protobuf/stubs/stringprintf.cc                        \google/protobuf/stubs/stringprintf.h                         \google/protobuf/stubs/structurally_valid.cc                  \google/protobuf/stubs/strutil.cc                             \google/protobuf/stubs/time.cc                                \google/protobuf/stubs/time.h                                 \google/protobuf/any_lite.cc                                  \google/protobuf/arena.cc                                     \google/protobuf/extension_set.cc                             \google/protobuf/generated_enum_util.cc                       \google/protobuf/generated_message_util.cc                    \google/protobuf/generated_message_table_driven_lite.h        \google/protobuf/generated_message_table_driven_lite.cc       \google/protobuf/implicit_weak_message.cc                     \google/protobuf/message_lite.cc                              \google/protobuf/parse_context.cc                             \google/protobuf/repeated_field.cc                            \google/protobuf/wire_format_lite.cc                          \google/protobuf/io/coded_stream.cc                           \google/protobuf/io/strtod.cc                                 \google/protobuf/io/zero_copy_stream.cc                       \google/protobuf/io/zero_copy_stream_impl.cc                  \google/protobuf/io/zero_copy_stream_impl_lite.cc		\google/protobuf/any.pb.cc                                    \google/protobuf/api.pb.cc                                    \google/protobuf/any.cc                                       \google/protobuf/descriptor.cc                                \google/protobuf/descriptor_database.cc                       \google/protobuf/descriptor.pb.cc                             \google/protobuf/duration.pb.cc                               \google/protobuf/dynamic_message.cc                           \google/protobuf/empty.pb.cc                                  \google/protobuf/extension_set_heavy.cc                       \google/protobuf/field_mask.pb.cc                             \google/protobuf/generated_message_reflection.cc              \google/protobuf/generated_message_table_driven_lite.h        \google/protobuf/generated_message_table_driven.cc            \google/protobuf/map_field.cc                                 \google/protobuf/message.cc                                   \google/protobuf/reflection_internal.h                        \google/protobuf/reflection_ops.cc                            \google/protobuf/service.cc                                   \google/protobuf/source_context.pb.cc                         \google/protobuf/struct.pb.cc                                 \google/protobuf/stubs/substitute.cc                          \google/protobuf/stubs/substitute.h                           \google/protobuf/text_format.cc                               \google/protobuf/timestamp.pb.cc                              \google/protobuf/type.pb.cc                                   \google/protobuf/unknown_field_set.cc                         \google/protobuf/wire_format.cc                               \google/protobuf/wrappers.pb.cc                               \google/protobuf/io/gzip_stream.cc                            \google/protobuf/io/printer.cc                                \google/protobuf/io/tokenizer.cc                              \google/protobuf/compiler/importer.cc                         \google/protobuf/compiler/parser.cc                           \google/protobuf/util/delimited_message_util.cc               \google/protobuf/util/field_comparator.cc                     \google/protobuf/util/field_mask_util.cc                      \google/protobuf/util/internal/constants.h                    \google/protobuf/util/internal/datapiece.cc                   \google/protobuf/util/internal/datapiece.h                    \google/protobuf/util/internal/default_value_objectwriter.cc  \google/protobuf/util/internal/default_value_objectwriter.h   \google/protobuf/util/internal/error_listener.cc              \google/protobuf/util/internal/error_listener.h               \google/protobuf/util/internal/expecting_objectwriter.h       \google/protobuf/util/internal/field_mask_utility.cc          \google/protobuf/util/internal/field_mask_utility.h           \google/protobuf/util/internal/json_escaping.cc               \google/protobuf/util/internal/json_escaping.h                \google/protobuf/util/internal/json_objectwriter.cc           \google/protobuf/util/internal/json_objectwriter.h            \google/protobuf/util/internal/json_stream_parser.cc          \google/protobuf/util/internal/json_stream_parser.h           \google/protobuf/util/internal/location_tracker.h             \google/protobuf/util/internal/mock_error_listener.h          \google/protobuf/util/internal/object_location_tracker.h      \google/protobuf/util/internal/object_source.h                \google/protobuf/util/internal/object_writer.cc               \google/protobuf/util/internal/object_writer.h                \google/protobuf/util/internal/protostream_objectsource.cc    \google/protobuf/util/internal/protostream_objectsource.h     \google/protobuf/util/internal/protostream_objectwriter.cc    \google/protobuf/util/internal/protostream_objectwriter.h     \google/protobuf/util/internal/proto_writer.cc                \google/protobuf/util/internal/proto_writer.h                 \google/protobuf/util/internal/structured_objectwriter.h      \google/protobuf/util/internal/type_info.cc                   \google/protobuf/util/internal/type_info.h                    \google/protobuf/util/internal/type_info_test_helper.cc       \google/protobuf/util/internal/type_info_test_helper.h        \google/protobuf/util/internal/utility.cc                     \google/protobuf/util/internal/utility.h                      \google/protobuf/util/json_util.cc                            \google/protobuf/util/message_differencer.cc                  \google/protobuf/util/time_util.cc                            \google/protobuf/util/type_resolver_util.ccLOCAL_EXPORT_C_INCLUDES :=
LOCAL_EXPORT_LDLIBS :=LOCAL_C_INCLUDES := $(LOCAL_PATH) \
$(LOCAL_PATH)/srcLOCAL_LDLIBS := -llog -lz#include $(BUILD_SHARED_LIBRARY)
include $(BUILD_STATIC_LIBRARY)

里面包含的文件很多，其实要包含的文件都在Makefile.am文件中：

有两个为 libprotobuf_lite_la_SOURCES 的文件全部包含进来。还要注意的是，我的APP_PLATFORM     := android-19,必须要下载 android-19 SDK，Android  SDK 可在https://www.androiddevtools.cn/index.html下载。

准备好上面现在开始编译：

Win+R  执行 cmd命令，进入c:/protobuf-3.12.0-rc2/src目录 输入：

ndk-build NDK_PROJECT_PATH=. APP_BUILD_SCRIPT=./android.mk NDK_APPLICATION_MK=./application.mk

会出现以下错误：

这个要修改一下C:/protobuf-3.12.0-rc2/src/google/protobuf/stubs/common.h文件就行了

打开加入下面内容：

#ifndef HAVE_PTHREAD
#define HAVE_PTHREAD
#endif

再次执行上次命令，就可以编译了：

这样就编译好了！