Late Form Alter

Provides new form alteration hooks that give developers a chance to alter form data after every other module has performed their own alterations.

hook_late_form_alter()
hook_late_form_BASE_FORM_ID_alter()
hook_late_form_FORM_ID_alter().

These are identical to hook_form_alter and its variations in every way except that the _late hooks should be called after all of the regular hooks.

This is accomplished by via hook_module_implements, as well as system weighting in order to compete with other modules or code attempting to change hook weighting via hook_module_implements.

See also:
Early Form Alter
http://drupal.org/project/early_form_alter