sqlite-src-3071401，版本为3.7.14.1，代码有四种模式，分别在不同状态下使用 SQLITE_MUTEX_OMIT 不适用互斥体的代码，初始化时，静态互斥体结构体不被覆盖。 SQLITE_MUTEX_NOOP 单线程应用时代码，没有提供互斥排它锁，初始化时，静态互斥体结构体被覆盖。 SQLITE_MUTEX_PTHREADS UNIX 多线程调用的代码 SQLITE_MUTEX_W32 WIN32下多线程调用的代码
/*
** Figure out what version of the code to use. The choices are
**
** SQLITE_MUTEX_OMIT No mutex logic. Not even stubs. The
** mutexes implemention cannot be overridden
** at start-time.//初始化时不被重置
**
** SQLITE_MUTEX_NOOP For single-threaded applications. No
** mutual exclusion is provided. But this
** implementation can be overridden at
** start-time.//只使用单进程调用
**
** SQLITE_MUTEX_PTHREADS For multi-threaded applications on Unix.//Unix调用
**
** SQLITE_MUTEX_W32 For multi-threaded applications on Win32.//Win32调用
*/