fix Issue 13757 - [CTFE] extern(C) alias declaration does not work in CTFE
fix Issue 13756 - [AA] Allow ref const index on foreach AA iteration
Merge pull request #4152 from 9rnsr/fix13756

Issue 13756 - [AA] Allow ref const index on foreach AA iteration
Merge pull request #4153 from 9rnsr/fix13757

Issue 13757 - [CTFE] extern(C) alias declaration does not work in CTFE
Preparation for the issue 13701 - Hijack object.dup(aa) call to emulate it in CTFE
Merge pull request #4154 from 9rnsr/ctfe_aa_dup

Preparation for the issue 13701 - Hijack object.dup(aa) call to emulate it in CTFE