[phobos] [D-Programming-Language/phobos] 10cbf7: use initOnce for lazy shared initialization

[GitHub via phobos]

  Branch: refs/heads/master
  Home:   https://github.com/D-Programming-Language/phobos
  Commit: 10cbf750f5514a2013009e0f2a0b5bbfc394eb6c
      https://github.com/D-Programming-Language/phobos/commit/10cbf750f5514a2013009e0f2a0b5bbfc394eb6c
  Author: Martin Nowak <code at dawg.eu>
  Date:   2015-02-11 (Wed, 11 Feb 2015)

  Changed paths:
    M std/concurrency.d
    M std/datetime.d
    M std/parallelism.d

  Log Message:
  -----------
  use initOnce for lazy shared initialization

- use TickDuration.currSystemTick instead of Clock.currSystemTick
  to break cyclic dependency of std.datetime and std.concurrency


  Commit: bcedffd0ee24ac6ebbeb5a88e679a698a7857e8d
      https://github.com/D-Programming-Language/phobos/commit/bcedffd0ee24ac6ebbeb5a88e679a698a7857e8d
  Author: Dmitry Olshansky <dmitry.olsh at gmail.com>
  Date:   2015-06-26 (Fri, 26 Jun 2015)

  Changed paths:
    M std/concurrency.d
    M std/datetime.d
    M std/parallelism.d

  Log Message:
  -----------
  Merge pull request #2943 from MartinNowak/useInitOnce

use initOnce for lazy shared initialization


Compare: https://github.com/D-Programming-Language/phobos/compare/ec0a0ad523d7...bcedffd0ee24