d: Turn on deprecation warnings by default.

d: Turn on deprecation warnings by default.

This is the default in the upstream reference compiler, and can reduce
some confusion when comparing warning/error messages of gdc and dmd side
by side.

Merges libphobos with upstream druntime d05ebaad and phobos 021ae0df7.

Reviewed-on: https://github.com/dlang/druntime/pull/3127
	     https://github.com/dlang/phobos/pull/7521

gcc/d/ChangeLog:

	* d-lang.cc (d_init_options): Turn on deprecation warnings by default.

libphobos/ChangeLog:

	* libdruntime/MERGE: Merge upstream druntime d05ebaad.
	* src/MERGE: Merge upstream phobos 021ae0df7.
	* testsuite/libphobos.typeinfo/struct-align.d: Remove empty statement.

gcc/testsuite/ChangeLog:

	* gdc.dg/asm1.d: Don't use deprecated asm syntax.
	* gdc.dg/compilable.d: Add public to selective import.
	* gdc.dg/lto/ltotests_0.d: Explicitly catch Throwable.
	* gdc.dg/runnable.d: Remove empty statement.