Static GC_dont_precollect 

pub unsafe static mut GC_dont_precollect: c_int

Do not collect as part of the collector initialization. Should be set only if the client wants a chance to manually initialize the root set before the first collection. Interferes with black-listing. Wizards only. The setter and the getter are unsynchronized (and no external locking is needed since the value is accessed at the collector initialization only).