InnoDB: Make UNIV_LOG_DEBUG work

innobase/buf/buf0flu.c:
  buf_flush_write_block_low(): Warn about UNIV_LOG_DEBUG only once
innobase/log/log0recv.c:
  log_block_checksum_is_ok_or_old_format(): Disable the check
  if UNIV_LOG_DEBUG is defined

innobase/buf/buf0flu.c

@@ -412,6 +412,9 @@ buf_flush_write_block_low(
 /*======================*/
 	buf_block_t*	block)	/* in: buffer block to write */
 {
+#ifdef UNIV_LOG_DEBUG
+	static ibool univ_log_debug_warned;
+#endif /* UNIV_LOG_DEBUG */
 	ut_a(block->state == BUF_BLOCK_FILE_PAGE);
 
 #ifdef UNIV_IBUF_DEBUG
@@ -420,8 +423,13 @@ buf_flush_write_block_low(
 	ut_ad(!ut_dulint_is_zero(block->newest_modification));
 
 #ifdef UNIV_LOG_DEBUG
-	fputs("Warning: cannot force log to disk in the log debug version!\n",
-		stderr);
+	if (!univ_log_debug_warned) {
+		univ_log_debug_warned = TRUE;
+		fputs(
+	"Warning: cannot force log to disk if UNIV_LOG_DEBUG is defined!\n"
+	"Crash recovery will not work!\n",
+			stderr);
+	}
 #else
 	/* Force the log to the disk before writing the modified block */
 	log_write_up_to(block->newest_modification, LOG_WAIT_ALL_GROUPS, TRUE);

innobase/log/log0recv.c

@@ -628,6 +628,9 @@ log_block_checksum_is_ok_or_old_format(
 			format of InnoDB version < 3.23.52 */
 	byte*	block)	/* in: pointer to a log block */
 {
+#ifdef UNIV_LOG_DEBUG
+	return(TRUE);
+#endif /* UNIV_LOG_DEBUG */
 	if (log_block_calc_checksum(block) == log_block_get_checksum(block)) {
 
 		return(TRUE);