Merge pull request #3738 from 9rnsr/fix13089

Issue 13089 - Spurious 'is not nothrow' error on static array initialization
Merge pull request #3788 from yebblies/arraytypes

[cleanup] Remove two unreferenced array types
Merge pull request #3787 from yebblies/sqrtport

[DDMD] Move sqrt into Port
Merge pull request #3793 from 9rnsr/fix13158

[REG2.066a] Issue 13158 - "void has no value" in std.variant.Algebraic (affects D:YAML)
Merge pull request #3794 from WalterBright/fix12057

fix Issue 12057 - [ICE], backend/cg87.c 925
Merge pull request #3797 from yebblies/cppscope

[DDMD] Issue 13182 - extern(C++) classes cause crash when allocated on the stack with scope
Merge pull request #3802 from ibuclaw/bug145

[2.066b] Issue 13194 - ICE when initializing static class members to void
Merge pull request #3798 from braddr/install-fix

change install target to match current release structure
Merge pull request #3801 from 9rnsr/fix13180

[REG2.066a] Issue 13180 - AA get returns const(char[]) instead of string
Merge pull request #3796 from yebblies/ddmdaav

[DDMD] Rename dmd associative array functions to avoid conflict with similarly named druntime functions
Merge pull request #3804 from 9rnsr/2.066

Cherry-picking commits from master to 2.066 branch (for beta6)