D7 upgrades fail with mysql 5.7:

This is also present in Drupal 7.43 when upgrading from Drupal 6. With PHP 5.6.20 and MySQL 5.7.9.1 I get
PDOException: SQLSTATE[42000]: Syntax error or access violation: 1171 All parts of a PRIMARY KEY must be NOT NULL; if you need NULL in a key, use UNIQUE instead: CREATE TABLE {system_update_7061} ( `vid` INT DEFAULT NULL, PRIMARY KEY (`vid`) ) ENGINE = InnoDB DEFAULT CHARACTER SET utf8 COMMENT 'Stores temporary data for system_update_7061.'; Array ( ) in db_create_table() (line 2720 of D:\Drupal\includes\database\database.inc).
for system_update_7061.
In my case I solved it by changing line 2796 of system.install to

'fields' => array('vid' => array('type' => 'int', 'default' => '0' )),

This patch looks good to me. It is probably also important/necessary to add #2615496: A serial/primary key field can not be added to an existing table for some databases to fully fix this problem.

There's a RTBC duplicate @ #2981248: MySQL 5.7 incompatibility in system upgrade 7061

Tests are passing on MySQL 5.7 so setting to RTBC.

this didn't make it into 7.60, bumping to 7.61

closing in favour of:

This has been fixed in 7.x today.

Thanks all.

C'est moi qui te remercie, Bonne année Pol!