d: Merge upstream dmd d7772a2369, phobos 5748ca43f.

In upstream dmd, the compiler front-end and run-time have been merged
together into one repository.  Both dmd and libdruntime now track that.

D front-end changes:

    - Deprecated `scope(failure)' blocks that contain `return' statements.
    - Deprecated using integers for `version' or `debug' conditions.
    - Deprecated returning a discarded void value from a function.
    - `new' can now allocate an associative array.

D runtime changes:

    - Added avx512f detection to core.cpuid module.

Phobos changes:

    - Changed std.experimental.logger.core.sharedLog to return
      shared(Logger).

gcc/d/ChangeLog:

	* dmd/MERGE: Merge upstream dmd d7772a2369.
	* dmd/VERSION: Bump version to v2.100.1.
	* d-codegen.cc (get_frameinfo): Check whether decision to generate
	closure changed since semantic finished.
	* d-lang.cc (d_handle_option): Remove handling of -fdebug=level and
	-fversion=level.
	* decl.cc (DeclVisitor::visit (VarDeclaration *)): Generate evaluation
	of noreturn variable initializers before throw.
	* expr.cc (ExprVisitor::visit (AssignExp *)): Don't generate
	assignment for noreturn types, only evaluate for side effects.
	* lang.opt (fdebug=): Undocument -fdebug=level.
	(fversion=): Undocument -fversion=level.

libphobos/ChangeLog:

	* configure: Regenerate.
	* configure.ac (libtool_VERSION): Update to 4:0:0.
	* libdruntime/MERGE: Merge upstream druntime d7772a2369.
	* libdruntime/Makefile.am (DRUNTIME_DSOURCES): Add
	core/internal/array/duplication.d.
	* libdruntime/Makefile.in: Regenerate.
	* src/MERGE: Merge upstream phobos 5748ca43f.
	* testsuite/libphobos.gc/nocollect.d: