d: Merge upstream dmd, druntime 26f049fb26, phobos 330d6a4fd.

D front-end changes:

	- Import dmd v2.105.0-beta.1.
	- Added predefined version identifier VisionOS (ignored by GDC).
	- Functions can no longer have `enum` storage class.
	- The deprecation of the `body` keyword has been reverted, it is
	  now an obsolete feature.
	- The error for `scope class` has been reverted, it is now an
	  obsolete feature.

D runtime changes:

	- Import druntime v2.105.0-beta.1.

Phobos changes:

	- Import phobos v2.105.0-beta.1.
	- AliasSeq has been removed from std.math.
	- extern(C) getdelim and getline have been removed from
	  std.stdio.

gcc/d/ChangeLog:

	* dmd/MERGE: Merge upstream dmd 26f049fb26.
	* dmd/VERSION: Bump version to v2.105.0-beta.1.
	* d-codegen.cc (get_frameinfo): Check useGC in condition.
	* d-lang.cc (d_handle_option): Set obsolete parameter when compiling
	with -Wall.
	(d_post_options): Set useGC to false when compiling with
	-fno-druntime.  Propagate obsolete flag to compileEnv.
	* expr.cc (ExprVisitor::visit (CatExp *)): Check useGC in condition.

libphobos/ChangeLog:

	* libdruntime/MERGE: Merge upstream druntime 26f049fb26.
	* src/MERGE: Merge upstream phobos 330d6a4fd.