cocos2d-x, protobuf, no config.h, #error "No suitable threading library available."

  在用cocos2d-x3.2 + protobuf编译Android项目的时候，protobuf出现了两个问题：

1. 首先是config.h找不到，查阅自后说是通过命令或工具生成的，里面的内容根据不同平台是不一样的（引用一些用到的库，例如hash_map,hash_set等，和部分宏定义），那么就要在自己手动生成，或者自己创建一个空的config，自己把一些引用到的库加进去，为了能快速编译通过，我就自己创建了一个config.h，没有引用任何库。

#ifndef _LINUX_CONFIG_H
#define _LINUX_CONFIG_H

#endif

然后找不到config.h的问题解决了。

2.  然后是error "No suitable threading library available."

定位到common.cc文件中

#ifdef _WIN32
#define WIN32_LEAN_AND_MEAN // We only need minimal includes
#include <windows.h>
#define snprintf _snprintf // see comment in strutil.cc
#elif defined(HAVE_PTHREAD)
#include <pthread.h>
#else
#error "No suitable threading library available."
#endif

发现是找不到HAVE_PTHREAD宏定义，导致没有引用pthread库，直接用#include <pthread.h>替换#error "No suitable threading library available."这句代码，又会导致其他文件找不到；那么可能其它地方也引用了HAVE_PTHREAD宏，那这个宏是protobuf库根据不同平台定义的呢，还是该我们自己加呢，如果是自己加又应该加在哪里呢？

联想到config文件找不到的问题，猜到可能是config文件中缺少一些代码，看来不能用空的config，那么就直接在config.h中加上 #define HAVE_PTHREAD 即可。

#ifndef _LINUX_CONFIG_H
#define _LINUX_CONFIG_H

#define HAVE_PTHREAD

#endif

 之后编译通过。。。

如果是有完美强迫症的、或者要求高效率（使用hash_map/unordered_map等），那么就在linux上用configure生成一个config.h吧，下面附上一个完整生成的：

/* config.h.  Generated from config.h.in by configure.  */
/* config.h.in.  Generated from configure.ac by autoheader.  */

/* the name of <hash_map> */
#define HASH_MAP_CLASS hash_map

/* the location of <unordered_map> or <hash_map> */
#define HASH_MAP_H <ext/hash_map>

/* the namespace of hash_map/hash_set */
#define HASH_NAMESPACE std::tr1

/* the name of <hash_set> */
#define HASH_SET_CLASS hash_set

/* the location of <unordered_set> or <hash_set> */
#define HASH_SET_H <ext/hash_set>

/* Define to 1 if you have the <dlfcn.h> header file. */
#define HAVE_DLFCN_H 1

/* Define to 1 if you have the <fcntl.h> header file. */
#define HAVE_FCNTL_H 1

/* Define to 1 if you have the `ftruncate' function. */
#define HAVE_FTRUNCATE 1

/* define if the compiler has hash_map */
#define HAVE_HASH_MAP 1

/* define if the compiler has hash_set */
#define HAVE_HASH_SET 1

/* Define to 1 if you have the <inttypes.h> header file. */
#define HAVE_INTTYPES_H 1

/* Define to 1 if you have the <limits.h> header file. */
#define HAVE_LIMITS_H 1

/* Define to 1 if you have the <memory.h> header file. */
#define HAVE_MEMORY_H 1

/* Define to 1 if you have the `memset' function. */
#define HAVE_MEMSET 1

/* Define to 1 if you have the `mkdir' function. */
#define HAVE_MKDIR 1

/* Define if you have POSIX threads libraries and header files. */
#define HAVE_PTHREAD 1

/* Define to 1 if you have the <stdint.h> header file. */
#define HAVE_STDINT_H 1

/* Define to 1 if you have the <stdlib.h> header file. */
#define HAVE_STDLIB_H 1

/* Define to 1 if you have the `strchr' function. */
#define HAVE_STRCHR 1

/* Define to 1 if you have the `strerror' function. */
#define HAVE_STRERROR 1

/* Define to 1 if you have the <strings.h> header file. */
#define HAVE_STRINGS_H 1

/* Define to 1 if you have the <string.h> header file. */
#define HAVE_STRING_H 1

/* Define to 1 if you have the `strtol' function. */
#define HAVE_STRTOL 1

/* Define to 1 if you have the <sys/stat.h> header file. */
#define HAVE_SYS_STAT_H 1

/* Define to 1 if you have the <sys/types.h> header file. */
#define HAVE_SYS_TYPES_H 1

/* Define to 1 if you have the <unistd.h> header file. */
#define HAVE_UNISTD_H 1

/* Enable classes using zlib compression. */
/* #undef HAVE_ZLIB */

/* Define to the sub-directory in which libtool stores uninstalled libraries.
   */
#define LT_OBJDIR ".libs/"

/* Name of package */
#define PACKAGE "protobuf"

/* Define to the address where bug reports for this package should be sent. */
#define PACKAGE_BUGREPORT "protobuf@googlegroups.com"

/* Define to the full name of this package. */
#define PACKAGE_NAME "Protocol Buffers"

/* Define to the full name and version of this package. */
#define PACKAGE_STRING "Protocol Buffers 2.5.0"

/* Define to the one symbol short name of this package. */
#define PACKAGE_TARNAME "protobuf"

/* Define to the home page for this package. */
#define PACKAGE_URL ""

/* Define to the version of this package. */
#define PACKAGE_VERSION "2.5.0"

/* Define to necessary symbol if this constant uses a non-standard name on
   your system. */
/* #undef PTHREAD_CREATE_JOINABLE */

/* Define to 1 if you have the ANSI C header files. */
#define STDC_HEADERS 1

/* Enable extensions on AIX 3, Interix.  */
#ifndef _ALL_SOURCE
# define _ALL_SOURCE 1
#endif
/* Enable GNU extensions on systems that have them.  */
#ifndef _GNU_SOURCE
# define _GNU_SOURCE 1
#endif
/* Enable threading extensions on Solaris.  */
#ifndef _POSIX_PTHREAD_SEMANTICS
# define _POSIX_PTHREAD_SEMANTICS 1
#endif
/* Enable extensions on HP NonStop.  */
#ifndef _TANDEM_SOURCE
# define _TANDEM_SOURCE 1
#endif
/* Enable general extensions on Solaris.  */
#ifndef __EXTENSIONS__
# define __EXTENSIONS__ 1
#endif


/* Version number of package */
#define VERSION "2.5.0"

/* Define to 1 if on MINIX. */
/* #undef _MINIX */

/* Define to 2 if the system does not provide POSIX.1 features except with
   this defined. */
/* #undef _POSIX_1_SOURCE */

/* Define to 1 if you need to in order for `stat' and other things to work. */
/* #undef _POSIX_SOURCE */