Consider using InitializeCriticalSectionEx on Vista and higher

[eholk]

Per a TODO (soon to be a FIXME) in lock_and_signal.cpp:

    // TODO? Consider checking GetProcAddress("InitializeCriticalSectionEx")
    // so Windows >= Vista we can use CRITICAL_SECTION_NO_DEBUG_INFO to avoid
    // allocating CRITICAL_SECTION debug info that is never released. See:
    // http://stackoverflow.com/questions/804848/
    //        critical-sections-leaking-memory-on-vista-win2008#889853

[bstrie]

The FIXME in question references #2893, which has been closed. Wondering if this should be closed as well.

[pcwalton]

Closing this because this should be done in Rust.