Index: src/alter.c
==================================================================
--- src/alter.c
+++ src/alter.c
@@ -265,11 +265,10 @@
   Column *pCol;             /* The new column */
   Expr *pDflt;              /* Default value for the new column */
   sqlite3 *db;              /* The database connection; */
   Vdbe *v;                  /* The prepared statement under construction */
   int r1;                   /* Temporary registers */
-  char *zWhere;             /* WHERE clause for reloading schema */
 
   db = pParse->db;
   if( pParse->nErr || db->mallocFailed ) return;
   pNew = pParse->pNewTable;
   assert( pNew );
@@ -397,11 +396,10 @@
 ** coding the "ALTER TABLE ... ADD" statement.
 */
 void sqlite3AlterBeginAddColumn(Parse *pParse, SrcList *pSrc){
   Table *pNew;
   Table *pTab;
-  Vdbe *v;
   int iDb;
   int i;
   int nAlloc;
   sqlite3 *db = pParse->db;
 
@@ -1290,23 +1288,18 @@
   sqlite3_context *context,
   int NotUsed,
   sqlite3_value **argv
 ){
   sqlite3 *db = sqlite3_context_db_handle(context);
-  char *zOutput = 0;
-  char *zResult;
-  unsigned char const *zDb = sqlite3_value_text(argv[0]);
-  unsigned char const *zInput = sqlite3_value_text(argv[1]);
-  unsigned char const *zOld = sqlite3_value_text(argv[2]);
-  unsigned char const *zNew = sqlite3_value_text(argv[3]);
+  const char *zDb = (const char*)sqlite3_value_text(argv[0]);
+  const char *zInput = (const char*)sqlite3_value_text(argv[1]);
+  const char *zOld = (const char*)sqlite3_value_text(argv[2]);
+  const char *zNew = (const char*)sqlite3_value_text(argv[3]);
   int bTemp = sqlite3_value_int(argv[4]);
+  UNUSED_PARAMETER(NotUsed);
 
   if( zInput && zOld && zNew ){
-    unsigned const char *z;         /* Pointer to token */
-    int n;                          /* Length of token z */
-    int token;                      /* Type of token */
-
     Parse sParse;
     int rc;
     int bQuote = 1;
     RenameCtx sCtx;
     Walker sWalker;
@@ -1412,21 +1405,20 @@
   sqlite3_context *context,
   int NotUsed,
   sqlite3_value **argv
 ){
   sqlite3 *db = sqlite3_context_db_handle(context);
-  unsigned char const *zDb = sqlite3_value_text(argv[0]);
-  unsigned char const *zInput = sqlite3_value_text(argv[1]);
+  char const *zDb = (const char*)sqlite3_value_text(argv[0]);
+  char const *zInput = (const char*)sqlite3_value_text(argv[1]);
   int bTemp = sqlite3_value_int(argv[4]);
 
-  if( zInput==0 ) return;
-
 #ifndef SQLITE_OMIT_AUTHORIZATION
   sqlite3_xauth xAuth = db->xAuth;
   db->xAuth = 0;
 #endif
 
+  UNUSED_PARAMETER(NotUsed);
   if( zDb && zInput ){
     int rc;
     Parse sParse;
     rc = renameParseSql(&sParse, zDb, 1, db, zInput, bTemp);
     if( rc==SQLITE_OK ){