db: enable SQLite extended result codes

With this change, we get more fine-grained error messages if something
goes wrong in the course of communicating with the SQLite database. To
pick some random examples, the error codes SQLITE_IOERR_NOMEM,
SQLITE_IOERR_CORRUPTFS or SQLITE_IOERR_FSYNC are way more specific
than just a plain SQLITE_IOERR, and the corresponding error messages
generated by sqlite3_errstr() will hence give a better hint to the
user (or also to the developers, if an error report is sent) what the
cause for a failure is.

Changelog-None

wallet/db_sqlite3.c

@@ -146,6 +146,12 @@ static bool db_sqlite3_setup(struct db *db)
 	}
 	wrapper->conn = sql;
 
+	err = sqlite3_extended_result_codes(wrapper->conn, 1);
+	if (err != SQLITE_OK) {
+		db_fatal("failed to enable extended result codes: %s",
+			 sqlite3_errstr(err));
+	}
+
 	if (!backup_filename)
 		wrapper->backup_conn = NULL;
 	else {