d: Merge upstream dmd, druntime a45f4e9f43, phobos 106038f2e.

D front-end changes:

	- Import dmd v2.103.1.
	- Deprecated invalid special token sequences inside token strings.

D runtime changes:

	- Import druntime v2.103.1.

Phobos changes:

	- Import phobos v2.103.1.

gcc/d/ChangeLog:

	* dmd/MERGE: Merge upstream dmd a45f4e9f43.
	* dmd/VERSION: Bump version to v2.103.1.

libphobos/ChangeLog:

	* libdruntime/MERGE: Merge upstream druntime a45f4e9f43.
	* src/MERGE: Merge upstream phobos 106038f2e.

(cherry picked from commit 55620c7b)