Rollup merge of #120672 - devnexen:update_thread_stack_guardpages_fbsd, r=m-ou-se

std::thread update freebsd stack guard handling.

up to now, it had been assumed the stack guard setting default is not touched in the field but some user might just want to disable it or increase it. checking it once at runtime should be enough.

Author: GuillaumeGomez