d: Merge upstream dmd d579c467c1, phobos 88aa69b14.

D front-end changes:

    - Throwing from contracts of `nothrow' functions has been
      deprecated, as this breaks the guarantees of `nothrow'.
    - Added language support for initializing the interior pointer of
      associative arrays using `new' keyword.

Phobos changes:

    - The std.digest.digest module has been removed.
    - The std.xml module has been removed.

gcc/d/ChangeLog:

	* dmd/MERGE: Merge upstream dmd d579c467c1.
	* decl.cc (layout_struct_initializer): Update for new front-end
	interface.
	* expr.cc (ExprVisitor::visit (AssignExp *)): Remove lowering of array
	assignments.
	(ExprVisitor::visit (NewExp *)): Add new lowering of new'ing
	associative arrays to an _aaNew() library call.
	* runtime.def (ARRAYSETASSIGN): Remove.
	(AANEW): Define.

libphobos/ChangeLog:

	* libdruntime/MERGE: Merge upstream druntime d579c467c1.
	* libdruntime/Makefile.am (DRUNTIME_DSOURCES): Remove
	rt/arrayassign.d.
	* libdruntime/Makefile.in: Regenerate.
	* src/MERGE: Merge upstream phobos 88aa69b14.
	* src/Makefile.am (PHOBOS_DSOURCES): Remove std/digest/digest.d,
	std/xml.d.
	* src/Makefile.in: Regenerate.