Fix bogus zero-length array test.

Issue 7175 was about .ptr always giving null for a zero-length
static array in a struct, despite the fact that the struct has
size 1 and thus certainly a non-null address.

The test case as modified by 36c9b64, however, checks that a
free-standing zero-length static array on the stack has an
address, which is quite a different scenario. From the spec,
I don't see a reason why zero-sized objects should need any
memory associated with them, so I am reluctant to pessimize
LDC's codegen over this.
Use an intermediate representation to reinterpret the value in Target::paintAsType
Fix Issue 3918 - Parameter use before its use in an AndAnd expression with reals treats NaN as false
Normalize backend's elf structures with system headers.
Forward to system headers when available.
Fix  Issue 12827 - [ICE] Segfault on immutable field self-initialization
Fix test output message
Fix test output message #2
fix Issue 13378 - Wrong failure of template value parameter deduction in IFTI
fix Issue 12531 - forward reference with nested struct
Remove special handling of delete aa[key].

This has been an error for a couple of years, and has been deprecated since pre D 1.0.
Remove special handling of old .offset property
Remove escape string literal error and improve error message
Remove error for old .typeinfo property
Fix Issue 5299 - Protected inheritance is semantically undefined

Deprecation -> Error
Fix Issue 3990 - Deferencing a dynamic array as pointer

Deprecation -> Error
[Refactoring] Define COLOR_* and use it for colorization.
fix Issue 13019 - Different color for "Warning:"

Choose colors: Warning -> light yellow, Deprecation -> light blue
fix Issue 13361 - Empty UDA accepted
Merge pull request #3919 from 9rnsr/fix13019

Issue 13019 - Different color for "Warning:"
Merge pull request #3898 from 9rnsr/fix13378

[REG2.066] Issue 13378 - Wrong failure of template value parameter deduction in IFTI