Index: src/sqliteInt.h
==================================================================
--- src/sqliteInt.h
+++ src/sqliteInt.h
@@ -112,19 +112,25 @@
 # define SQLITE_INT_TO_PTR(X)  ((void*)(X))
 # define SQLITE_PTR_TO_INT(X)  ((int)(X))
 #endif
 
 /*
-** The SQLITE_THREADSAFE macro must be defined as either 0 or 1.
+** The SQLITE_THREADSAFE macro must be defined as 0, 1, or 2.
+** 0 means mutexes are permanently disable and the library is never
+** threadsafe.  1 means the library is serialized which is the highest
+** level of threadsafety.  2 means the libary is multithreaded - multiple
+** threads can use SQLite as long as no two threads try to use the same
+** database connection at the same time.
+**
 ** Older versions of SQLite used an optional THREADSAFE macro.
-** We support that for legacy
+** We support that for legacy.
 */
 #if !defined(SQLITE_THREADSAFE)
 #if defined(THREADSAFE)
 # define SQLITE_THREADSAFE THREADSAFE
 #else
-# define SQLITE_THREADSAFE 1
+# define SQLITE_THREADSAFE 1 /* IMP: R-07272-22309 */
 #endif
 #endif
 
 /*
 ** The SQLITE_DEFAULT_MEMSTATUS macro must be defined as either 0 or 1.

Index: src/vdbemem.c
==================================================================
--- src/vdbemem.c
+++ src/vdbemem.c
@@ -959,11 +959,11 @@
       assert( (pVal->flags & (MEM_Ephem|MEM_Static))!=0 );
       if( sqlite3VdbeMemMakeWriteable(pVal)!=SQLITE_OK ){
         return 0;
       }
     }
-    sqlite3VdbeMemNulTerminate(pVal);
+    sqlite3VdbeMemNulTerminate(pVal); /* IMP: R-59893-45467 */
   }else{
     assert( (pVal->flags&MEM_Blob)==0 );
     sqlite3VdbeMemStringify(pVal, enc);
     assert( 0==(1&SQLITE_PTR_TO_INT(pVal->z)) );
   }