Relax isPOD rules so ctors don't make structs non-POD
Issue 11503 - immutable return value from pure function implicitly converts to mutable.
Remove CallExp::implicitCastTo altogether.

The pure -> immutable case is checked in implicitConvTo as well,
and since it yields MATCHexact, the castTo() in
Expression::implicitCastTo is a no-op anyway.
Issue 11909 - Struct members and static arrays break pure function escape analysis (immutability violation).
Clarify traverseIndirections implementation.

No functional change intended.
Make traverseIndirections() return bool instead of int.
C++ mangle. Additional cases and tests for unix.

class mangle, volatile et c.
disable array passing test

disable static array arguments mangling.
disable a ctor mangling
Merge pull request #3116 from IgorStepanov/cppmangleunix

C++ mangle. Additional cases and tests for unix.
Fix some new D incompatibilities
Disable rtti
Move TypeInfo::toDt into a visitor class
Merge pull request #3152 from yebblies/ddmdpatch

[DDMD] Fix some new D incompatibilities
Use a different token type for hex strings
Merge pull request #3155 from yebblies/typeinfodtvisitor

[DDMD] [refactor] Move TypeInfo::toDt into a visitor class
Merge pull request #3146 from yebblies/hextoken

[trivial] Use a different token type for hex strings
Merge pull request #3153 from yebblies/nortti

[DDMD] Disable rtti
Use writeByte everywhere instead of having writeByte and writebyte
Call extractString instead of manually null-terminating and extracting