[sql] Import reference version of SQLite 3.8.7.4.

third_party/sqlite/sqlite-src-3080704/src/mutex.c

 /*
 ** 2007 August 14
 **
 ** The author disclaims copyright to this source code.  In place of
 ** a legal notice, here is a blessing:
 **
 **    May you do good and not evil.
 **    May you find forgiveness for yourself and forgive others.
 **    May you share freely, never taking more than you give.
 **
@@ skipping 63 matching lines @@
 #endif
 
   return rc;
 }
 
 /*
 ** Retrieve a pointer to a static mutex or allocate a new dynamic one.
 */
 sqlite3_mutex *sqlite3_mutex_alloc(int id){
 #ifndef SQLITE_OMIT_AUTOINIT
-  if( sqlite3_initialize() ) return 0;
+  if( id<=SQLITE_MUTEX_RECURSIVE && sqlite3_initialize() ) return 0;
 #endif
   return sqlite3GlobalConfig.mutex.xMutexAlloc(id);
 }
 
 sqlite3_mutex *sqlite3MutexAlloc(int id){
   if( !sqlite3GlobalConfig.bCoreMutex ){
     return 0;
   }
   assert( GLOBAL(int, mutexIsInit) );
   return sqlite3GlobalConfig.mutex.xMutexAlloc(id);
@@ skipping 48 matching lines @@
 ** intended for use inside assert() statements.
 */
 int sqlite3_mutex_held(sqlite3_mutex *p){
   return p==0 || sqlite3GlobalConfig.mutex.xMutexHeld(p);
 }
 int sqlite3_mutex_notheld(sqlite3_mutex *p){
   return p==0 || sqlite3GlobalConfig.mutex.xMutexNotheld(p);
 }
 #endif
 
-#endif /* SQLITE_MUTEX_OMIT */
+#endif /* !defined(SQLITE_MUTEX_OMIT) */