libphobos: Merge phobos and druntime with upstream.

libphobos: Merge phobos and druntime with upstream.

Commits merged from druntime.

    Fix struct tls_index definition on x32
    https://github.com/dlang/druntime/pull/2354

    Update SectionGroup signatures to match on all targets
    https://github.com/dlang/druntime/pull/2401

    Fix issue 19128 - argument to alloca may be too large
    https://github.com/dlang/druntime/pull/2409

    Define some common filesystem limits in core.stdc.limits
    https://github.com/dlang/druntime/pull/2460

    Use version Darwin instead of OSX in core.sys.posix.aio
    https://github.com/dlang/druntime/pull/2470

Commits merged from phobos.

    Don't run HardFloat tests on SoftFloat systems
    https://github.com/dlang/phobos/pull/5358

    Remove reliance on stdin, stdout, stderr being aliasable
    https://github.com/dlang/phobos/pull/5718

    Solaris: add import clock_gettime to currStdTime
    https://github.com/dlang/phobos/pull/5807

    Don't print debug messages when building unittests
    https://github.com/dlang/phobos/pull/6827

    Add HPPA support to phobos
    Fixes https://gcc.gnu.org/PR89054
    https://github.com/dlang/phobos/pull/6836

From-SVN: r268293