[sql] Rewrite sqlite patching "system".

third_party/sqlite/fts3.patch

-diff --git ext/fts3/fts3.c ext/fts3/fts3.c
-index 20da051..71e22ae 100644
---- ext/fts3/fts3.c
-+++ ext/fts3/fts3.c
-@@ -291,6 +291,7 @@
- ** deletions and duplications.  This would basically be a forced merge
- ** into a single segment.
- */
-+#define CHROMIUM_FTS3_CHANGES 1
- 
- #if !defined(SQLITE_CORE) || defined(SQLITE_ENABLE_FTS3)
- 
-@@ -1226,7 +1227,13 @@ static int fts3ScanInteriorNode(
-     isFirstTerm = 0;
-     zCsr += sqlite3Fts3GetVarint32(zCsr, &nSuffix);
-     
--    if( nPrefix<0 || nSuffix<0 || &zCsr[nSuffix]>zEnd ){
-+    /* NOTE(shess): Previous code checked for negative nPrefix and
-+    ** nSuffix and suffix overrunning zEnd.  Additionally corrupt if
-+    ** the prefix is longer than the previous term, or if the suffix
-+    ** causes overflow.
-+    */
-+    if( nPrefix<0 || nSuffix<0 || nPrefix>nBuffer
-+     || &zCsr[nSuffix]<zCsr || &zCsr[nSuffix]>zEnd ){
-       rc = SQLITE_CORRUPT;
-       goto finish_scan;
-     }
-@@ -3646,7 +3660,11 @@ int sqlite3Fts3Init(sqlite3 *db){
-   ** module with sqlite.
-   */
-   if( SQLITE_OK==rc 
-+#if CHROMIUM_FTS3_CHANGES && !SQLITE_TEST
-+      /* fts3_tokenizer() disabled for security reasons. */
-+#else
-    && SQLITE_OK==(rc = sqlite3Fts3InitHashTable(db, pHash, "fts3_tokenizer"))
-+#endif
-    && SQLITE_OK==(rc = sqlite3_overload_function(db, "snippet", -1))
-    && SQLITE_OK==(rc = sqlite3_overload_function(db, "offsets", 1))
-    && SQLITE_OK==(rc = sqlite3_overload_function(db, "matchinfo", 1))
-@@ -3656,11 +3674,15 @@ int sqlite3Fts3Init(sqlite3 *db){
-     rc = sqlite3_create_module_v2(
-         db, "fts3", &fts3Module, (void *)pHash, hashDestroy
-     );
-+#if CHROMIUM_FTS3_CHANGES && !SQLITE_TEST
-+    /* Disable fts4 pending review. */
-+#else
-     if( rc==SQLITE_OK ){
-       rc = sqlite3_create_module_v2(
-           db, "fts4", &fts3Module, (void *)pHash, 0
-       );
-     }
-+#endif
-     return rc;
-   }
- 
-diff --git ext/fts3/fts3_icu.c ext/fts3/fts3_icu.c
-index 85390d3..a75b14a 100644
---- ext/fts3/fts3_icu.c
-+++ ext/fts3/fts3_icu.c
-@@ -198,7 +198,7 @@ static int icuNext(
- 
-     while( iStart<iEnd ){
-       int iWhite = iStart;
--      U8_NEXT(pCsr->aChar, iWhite, pCsr->nChar, c);
-+      U16_NEXT(pCsr->aChar, iWhite, pCsr->nChar, c);
-       if( u_isspace(c) ){
-         iStart = iWhite;
-       }else{