Fix a discrepancy between the documented behavior of SQLITE_DBCONFIG_LOOKASIDE
and what it actually does.  Also add evidence marks on the DBCONFIG_LOOKASIDE
implementation.

FossilOrigin-Name: f483be441323e1cb91516964cd6ab0edecad4366
diff --git a/src/main.c b/src/main.c
index 3dbab01..7b4fa25 100644
--- a/src/main.c
+++ b/src/main.c
@@ -453,12 +453,12 @@
     sz = 0;
     pStart = 0;
   }else if( pBuf==0 ){
-    sz = ROUND8(sz);
+    sz = ROUNDDOWN8(sz); /* IMP: R-33038-09382 */
     sqlite3BeginBenignMalloc();
-    pStart = sqlite3Malloc( sz*cnt );
+    pStart = sqlite3Malloc( sz*cnt );  /* IMP: R-61949-35727 */
     sqlite3EndBenignMalloc();
   }else{
-    sz = ROUNDDOWN8(sz);
+    sz = ROUNDDOWN8(sz); /* IMP: R-33038-09382 */
     pStart = pBuf;
   }
   db->lookaside.pStart = pStart;
@@ -501,14 +501,14 @@
   va_start(ap, op);
   switch( op ){
     case SQLITE_DBCONFIG_LOOKASIDE: {
-      void *pBuf = va_arg(ap, void*);
-      int sz = va_arg(ap, int);
-      int cnt = va_arg(ap, int);
+      void *pBuf = va_arg(ap, void*); /* IMP: R-21112-12275 */
+      int sz = va_arg(ap, int);       /* IMP: R-47871-25994 */
+      int cnt = va_arg(ap, int);      /* IMP: R-04460-53386 */
       rc = setupLookaside(db, pBuf, sz, cnt);
       break;
     }
     default: {
-      rc = SQLITE_ERROR;
+      rc = SQLITE_ERROR; /* IMP: R-42790-23372 */
       break;
     }
   }
@@ -1299,8 +1299,8 @@
 */
 int sqlite3_wal_autocheckpoint(sqlite3 *db, int nFrame){
 #ifdef SQLITE_OMIT_WAL
-  UNUSED_PARAMETER(db);

-  UNUSED_PARAMETER(nFrame);

+  UNUSED_PARAMETER(db);
+  UNUSED_PARAMETER(nFrame);
 #else
   if( nFrame>0 ){
     sqlite3_wal_hook(db, sqlite3WalDefaultHook, SQLITE_INT_TO_PTR(nFrame));