Merge the latest enhancements from trunk.

FossilOrigin-Name: 7bde6d4d8cf05e1beb9bdf20b85760dc3e7a76c9

src/shell.c

@@ -4619,6 +4619,13 @@ int SQLITE_CDECL main(int argc, char **argv){
   }
   data.out = stdout;
 
+#ifdef SQLITE_ENABLE_JSON1
+  {
+    extern int sqlite3_json_init(sqlite3*);
+    sqlite3_auto_extension((void(*)(void))sqlite3_json_init);
+  }
+#endif
+
   /* Go ahead and open the database file if it already exists.  If the
   ** file does not exist, delay opening it.  This prevents empty database
   ** files from being created if a user mistypes the database name argument