tdb2: clear bogus gcc uninitialized warnings with -O3

ccan/tdb2/test/run-11-simple-fetch.c

@@ -43,7 +43,7 @@ int main(int argc, char *argv[])
 			       O_RDWR|O_CREAT|O_TRUNC, 0600, &tap_log_attr);
 		ok1(tdb);
 		if (tdb) {
-			struct tdb_data d;
+			struct tdb_data d = { NULL, 0 }; /* Bogus GCC warning */
 
 			/* fetch should fail. */
 			failtest_suppress = false;

ccan/tdb2/test/run-12-store.c

@@ -50,7 +50,7 @@ int main(int argc, char *argv[])
 		/* We seemed to lose some keys.
 		 * Insert and check they're in there! */
 		for (j = 0; j < 500; j++) {
-			struct tdb_data d;
+			struct tdb_data d = { NULL, 0 }; /* Bogus GCC warning */
 			ok1(tdb_store(tdb, key, data, TDB_REPLACE) == 0);
 			ok1(tdb_fetch(tdb, key, &d) == TDB_SUCCESS);
 			ok1(equal(d, data));

ccan/tdb2/test/run-25-hashoverload.c

@@ -38,7 +38,7 @@ int main(int argc, char *argv[])
 
 	plan_tests(6883);
 	for (i = 0; i < sizeof(flags) / sizeof(flags[0]); i++) {
-		struct tdb_data d;
+		struct tdb_data d = { NULL, 0 }; /* Bogus GCC warning */
 
 		tdb = tdb_open("run-25-hashoverload.tdb", flags[i],
 			       O_RDWR|O_CREAT|O_TRUNC, 0600, &hattr);

ccan/tdb2/transaction.c

@@ -745,11 +745,12 @@ static void set_recovery_header(struct tdb_recovery_record *rec,
 static enum TDB_ERROR transaction_setup_recovery(struct tdb_context *tdb,
 						 tdb_off_t *magic_offset)
 {
-	tdb_len_t recovery_size;
+	/* Initialized for GCC's 4.4.5 overzealous uninitialized warnings. */
+	tdb_len_t recovery_size = 0;
+	tdb_off_t recovery_offset = 0, recovery_max_size = 0;
 	unsigned char *data, *p;
 	const struct tdb_methods *methods = tdb->transaction->io_methods;
 	struct tdb_recovery_record *rec;
-	tdb_off_t recovery_offset, recovery_max_size;
 	tdb_off_t old_map_size = tdb->transaction->old_map_size;
 	uint64_t magic, tailer;
 	int i;