Marina Glancy authored Feb 17, 2021 and Eloy Lafuente committed May 06, 2021

passing null to getdate() has different results in PHP7 and PHP8

See also 643b0cca.

 * The button to "Add group/grouping access restriction" under
   common module settings should only be present if corresponding
   availability plugins are enabled; and
 * Prevent the same button behaving as a submit button, which
   intercepted the user hitting return in the form and added a
   restriction without deliberate action taken by the user.

This isn't really a deprecations where something is replaced
by another and all uses must adapt to. Instead it's just a
fallback functionality that will stop working in Moodle 4.2.

Because of that, I've tried to add TODO/@todo comments to
the places that will need to modified, always pointing to
MDL-71421 that is where the removal will happen.

Also, haven't added any debugging() output, after thinking
a lot about it, because this isn't anything that developers
can be using but a internal implementation detail (a fallback)
that we want to remove in some versions.

The %P modifier is not supported in the macOS (MDL-71549)

1) The GROUP BY statement must include all fields in the SELECT
   not being aggregated or constant cols.
2) There was a missing space causing problems to databases
   using named parameters.

In order to allow for correct seb:// or sebs:// calls without browser
warnings of insecure links, it is not possible to send a get request
with an attached cmid parameter to the unknown seb:// or sebs://
URL via a form button.
We've got to use a <a href> link outside a form to circumvent
browsers warning of an insecure link and call Safe Exam Browser
correctly.

Change the yes/no dropdowns to a checkbox. Defaults to unchecked.