Workaround for MSAN bug needed

diff --git a/libmariadb/mariadb_stmt.c b/libmariadb/mariadb_stmt.c

index 8f5bddc..e15e1bd 100644

--- a/libmariadb/mariadb_stmt.c

+++ b/libmariadb/mariadb_stmt.c

@@ -1,5 +1,5 @@

 /****************************************************************************

-  Copyright (C) 2012 Monty Program AB

+  Copyright (C) 2012, 2020, MariaDB Corporation.

   This library is free software; you can redistribute it and/or

   modify it under the terms of the GNU Library General Public

@@ -56,7 +56,12 @@

 #include <mysql/client_plugin.h>

 #include <ma_common.h>

 #include "ma_priv.h"

-

+#ifndef __has_feature

+# define __has_feature(x) 0

+#endif

+#if __has_feature(memory_sanitizer)

+# include <sanitizer/msan_interface.h>

+#endif

 #define UPDATE_STMT_ERROR(stmt)\

 SET_CLIENT_STMT_ERROR((stmt), (stmt)->mysql->net.last_errno, (stmt)->mysql->net.sqlstate, (stmt)->mysql->net.last_error)

@@ -542,7 +547,13 @@ int store_param(MYSQL_STMT *stmt, int column, unsigned char **p, unsigned long r

     (*p) += 4;

     break;

   case MYSQL_TYPE_DOUBLE:

+#if __has_feature(memory_sanitizer)         /* QQ: MSAN has double trouble? */

+    __msan_check_mem_is_initialized(buf, sizeof(double));

+#endif

     float8store(*p, (*(double *)buf));

+#if __has_feature(memory_sanitizer)        /* QQ: MSAN has double trouble? */

+    __msan_unpoison(*p, sizeof(double));

+#endif

     (*p) += 8;

     break;

   case MYSQL_TYPE_LONGLONG: