[D-runtime] [D-Programming-Language/druntime] 34693f: make __setArrayAllocLength really pure

[GitHub via D-runtime]

  Branch: refs/heads/master
  Home:   https://github.com/D-Programming-Language/druntime
  Commit: 34693f48db9c49879c53e451a899f305f7600ff3
      https://github.com/D-Programming-Language/druntime/commit/34693f48db9c49879c53e451a899f305f7600ff3
  Author: Martin Nowak <code at dawg.eu>
  Date:   2015-03-06 (Fri, 06 Mar 2015)

  Changed paths:
    M src/rt/lifetime.d

  Log Message:
  -----------
  make __setArrayAllocLength really pure

- use compare-and-swap instead of synchronized
  as the latter isn't really pure

- using cas instead of a global mutex
  also heavily reduces contention


  Commit: c7f5b2cd595e5b208b960fecd6e7271540d48c06
      https://github.com/D-Programming-Language/druntime/commit/c7f5b2cd595e5b208b960fecd6e7271540d48c06
  Author: Steven Schveighoffer <schveiguy at yahoo.com>
  Date:   2015-03-13 (Fri, 13 Mar 2015)

  Changed paths:
    M src/rt/lifetime.d

  Log Message:
  -----------
  Merge pull request #1187 from MartinNowak/pureSetArrayAllocLength

make __setArrayAllocLength really pure


Compare: https://github.com/D-Programming-Language/druntime/compare/84059dbf4163...c7f5b2cd595e