[sql] Import reference version of SQLite 3.7.6.3.

third_party/sqlite/sqlite-src-3070603/src/vdbemem.c

 /*
 ** 2004 May 26
 **
 ** 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 1139 matching lines @@
   Mem *p = (Mem*)pVal;
   if( (p->flags & MEM_Blob)!=0 || sqlite3ValueText(pVal, enc) ){
     if( p->flags & MEM_Zero ){
       return p->n + p->u.nZero;
     }else{
       return p->n;
     }
   }
   return 0;
 }