Fix issue 12965 - DMD sets ELFOSABI to ELFOSABI_LINUX on all systems
Fixed comment alignment; added #error for undefined ELF ABIs
fix Issue 12970 - Enclosing @system attribute is precedence than postfix @safe
Merge pull request #3687 from jasonbking/osabi

Fix issue 12965 - DMD sets ELFOSABI to ELFOSABI_LINUX on all systems
Fix Linux/64 compile error.
Merge pull request #3691 from quickfur/missing_endif

Fix Linux/64 compile error introduced by pull #1296
Fix issue 12968 - Incorrect codgen for xchg with R8
Merge pull request #3690 from Orvid/issue12968

Fix issue 12968 - incorrect codegen
Ddoc should output qualified anchors for template members.

Fixes [issue 10366] (https://issues.dlang.org/show_bug.cgi?id=10366).
Add tests for issue 10366.
Update ddoc test outputs to have qualified anchors.
Merge pull request #3693 from quickfur/ddoc_qualified_anchors

Implement ddoc qualified anchors for template members
Merge pull request #3688 from 9rnsr/fix12970

Issue 12970 - Enclosing @system attribute is precedence than postfix @safe
fix Issue 12900 - Wrong code in IfStatement condition Expression
[WS] Replace tab with spaces.

Tab was added in d8e5f55c9b94e831b6d178a20e34144933c3fc32.
Merge pull request #3694 from denis-sh/ws-fixup-pull-3687

[Whitespace] Replace tab with spaces.
Merge pull request #3685 from 9rnsr/fix12900

More conservative fix for issue 12900 - Wrong code in IfStatement condition Expression
Remove commented code, printf's etc
Add optimize methods for UnaExp and BinExp
Add const checking methods for UnaExp and BinExp