Further polish SQLite vendoring

- Now integrated with `make tags` for Emacs IDE features
- Delete some old deprecated broken full-text search engines
- Rename .h → .inc files that don't meet our definition of header
- Make sure every #include line is normal form so tools understand

See #162

third_party/sqlite3/sqlite3ext.h

@@ -1,24 +1,15 @@
+#ifndef SQLITE3EXT_H
+#define SQLITE3EXT_H
+#include "third_party/sqlite3/sqlite3.h"
+/* clang-format off */
+
 /*
-** 2006 June 7
-**
-** 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 defines the SQLite interface for use by
 ** shared libraries that want to be imported as extensions into
 ** an SQLite instance.  Shared libraries that intend to be loaded
 ** as extensions by SQLite should #include this file instead of
 ** sqlite3.h.
 */
-#ifndef SQLITE3EXT_H
-#define SQLITE3EXT_H
-#include "third_party/sqlite3/sqlite3.h"
-/* clang-format off */
 
 /*
 ** The following structure holds pointers to all of the SQLite API