prng: Add a global fast PRNG object

prop289 needs to have a fast PRNG allocated early in order to avoid creating a fast prng object every time we want to add random to a cell.

changed milestone to %Tor: 0.4.1.x-final in legacy/trac

Trac:
Parent Ticket: legacy/trac#26288 (moved)

added actualpoints::.1 in Legacy / Trac component::core tor/tor in Legacy / Trac milestone::Tor: 0.4.1.x-final in Legacy / Trac owner::nickm in Legacy / Trac parent::26288 in Legacy / Trac points::0.1 in Legacy / Trac priority::medium in Legacy / Trac prng in Legacy / Trac prop289 in Legacy / Trac resolution::fixed in Legacy / Trac reviewer::dgoulet in Legacy / Trac severity::normal in Legacy / Trac sponsor::V in Legacy / Trac status::closed in Legacy / Trac tor-relay in Legacy / Trac type::enhancement in Legacy / Trac labels

(this actually wants to be thread-local, for performance reasons)

See branch thread_rng with PR at https://github.com/torproject/tor/pull/714

Trac:
Actualpoints: N/A to .1
Status: assigned to needs_review

lgtm;

Trac:
Status: needs_review to merge_ready

Merged to master!

Trac:
Resolution: N/A to fixed
Status: merge_ready to closed

closed

changed time estimate to 48m

added 48m of time spent

mentioned in issue legacy/trac#29542 (moved)

moved from legacy/trac#29536 (moved)

added Feature label and removed 1 deleted label

added Relay label and removed 1 deleted label