SHOW CREATE TABLE does not parenthesize default expressions

When printing the CREATE TABLE to reconstruct a table, the SHOW CREATE TABLE command does not wrap default expressions with parenthesis.

I'd enter this as 'trivial', except that it breaks the DDL parsers for a surprisingly large number of GUI-style management tools, including SQL Workbench, SEQUEL Pro, and a surprising number of others. Wrapping the expression with parens on output should be non-breaking, as parens are always permitted in this context. A widespread practical impact is that tables defined with a text-to-binary16 UUID initializer

Example from MariaDB 10.4.6: note the output for the guid column in:

| station | CREATE TABLE `station` (

  `id` int(11) NOT NULL AUTO_INCREMENT,

  `name` varchar(45) NOT NULL,

  `where` varchar(45) NOT NULL,

  `description` varchar(255) DEFAULT NULL,

  `guid` binary(16) NOT NULL DEFAULT unhex(replace(uuid(),'-','')),

  PRIMARY KEY (`id`,`where`),

  UNIQUE KEY `name_UNIQUE` (`name`),

  UNIQUE KEY `ID_UNIQUE` (`id`),

  UNIQUE KEY `guid_UNIQUE` (`guid`)

) ENGINE=InnoDB AUTO_INCREMENT=4 DEFAULT CHARSET=utf8mb4 |