Synchronizing with the upstream release of v2.109.1.

D front-end changes:

	- Import dmd v2.109.1.
	- Copying from `const(void)[]' to `void[]' is now disallowed
	  with `-fpreview=fiximmutableconv'.
	- Import expressions are now treated as hex strings.
	- Using boolean values other than 0 or 1 in `@safe' code is now
	  deprecated.

D runtime changes:

	- Import dmd v2.109.1.

Phobos changes:

	- Import dmd v2.109.1.

gcc/d/ChangeLog:

	* dmd/MERGE: Merge upstream dmd 66b93fc24a.
	* dmd/VERSION: Bump version to v2.109.1.
	* d-builtins.cc (build_frontend_type): Update for new front-end
	interface.
	(matches_builtin_type): Likewise.
	* d-codegen.cc (identity_compare_p): Likewise.
	(call_side_effect_free_p): Likewise.
	* d-convert.cc (convert_expr): Likewise.
	(check_valist_conversion): Likewise.
	* d-lang.cc (d_types_compatible_p): Likewise.
	* d-target.cc (Target::isVectorTypeSupported): Likewise.
	(Target::isReturnOnStack): Likewise.
	(Target::preferPassByRef): Likewise.
	* decl.cc (class DeclVisitor): Likewise.
	* expr.cc (class ExprVisitor): Likewise.
	* typeinfo.cc (class TypeInfoVisitor): Likewise.
	* types.cc (class TypeVisitor): Likewise.

libphobos/ChangeLog:

	* libdruntime/MERGE: Merge upstream druntime 66b93fc24a.
	* src/MERGE: Merge upstream phobos 0c28620c3.
	* src/Makefile.am (PHOBOS_DSOURCES): Add
	std/internal/test/sumtype_example_overloads.d.
	* src/Makefile.in: Regenerate.