Added sqlite-preprocessed-3350500

From https://www.sqlite.org/2021/sqlite-preprocessed-3350500.zip

third_party/sqlite3/sqliteicu.h

@@ -0,0 +1,26 @@
+/*
+** 2008 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.
+**
+******************************************************************************
+**
+** This header file is used by programs that want to link against the
+** ICU extension.  All it does is declare the sqlite3IcuInit() interface.
+*/
+#include "sqlite3.h"
+
+#ifdef __cplusplus
+extern "C" {
+#endif  /* __cplusplus */
+
+int sqlite3IcuInit(sqlite3 *db);
+
+#ifdef __cplusplus
+}  /* extern "C" */
+#endif  /* __cplusplus */