d: Merge upstream dmd eb7bee331, druntime 27834edb, phobos ac296f80c.

D front-end changes:

    - Import dmd v2.100.0-beta.1.
    - Print deprecation messages for scope violations unless
      `-frevert=dip1000' is used.
    - Fixed a missed case of switch case fallthrough not being caught by
      the compiler.

D runtime changes:

    - Import druntime v2.100.0-beta.1.

Phobos changes:

    - Import phobos v2.100.0-beta.1.

gcc/d/ChangeLog:

	* dmd/MERGE: Merge upstream dmd eb7bee331.
	* dmd/VERSION: Update version to v2.100.0-beta.1.
	* d-lang.cc (d_handle_option): Handle OPT_frevert_dip1000.
	* lang.opt (frevert=dip1000): New option.

libphobos/ChangeLog:

	* libdruntime/MERGE: Merge upstream druntime 27834edb.
	* src/MERGE: Merge upstream phobos ac296f80c.
	* src/Makefile.am (PHOBOS_DSOURCES): Add std/int128.d.
	* src/Makefile.in: Regenerate.