There cannot be undefined behavior at compile time, so these warnings can be
ignored when `offsetof` is used in a static assert:
```
warning: offset of on non-standard-layout type 'AsyncTask' [-Winvalid-offsetof]
```
Replace NextLinkType with Item::Kind with more clear definition.
Use llvm::PointerIntPair<>.
Use hierarchy of classes instead of optional fields inside Item.
Combined Storage::copyToOnlyOnlyFromCurrentGroup() into Storage::initializeLinkParent().
Also create parent task marker when copying items created inside withTaskGroup().
Removed Storage::peekHeadLinkType().
rdar://138085348
Even though errors are ObjC boxes, they can't be tagged pointers and in fact may use that bit to store enum tags, so treating them like regular ObjC references here can cause ref count issues.
`Builtin.FixedArray<let N: Int, T: ~Copyable & ~Escapable>` has the layout of `N` elements of type `T` laid out
sequentially in memory (with the tail padding of every element occupied by the array). This provides a primitive
on which the standard library `Vector` type can be built.
In Xcode 16 SDKs there seem to be two `errno` visible for some files,
one in the `Darwin` module, and one in the `_errno` module (which seems
new for this Xcode version).
Disambiguate the references by prepending `Darwin`, which should be the
one that was being used before Xcode 16 SDKs.
Also remove the code that deals with file descriptors; we will now
only start the backtracer for processes that have the get-task-allow
entitlement, which means that they've been specifically signed for
debugging, and *that* means that it is no longer critical to ensure
that unexpectedly inherited fds are closed.
rdar://137551812
The existing CMake code for macCatalyst swiftmodule only handled the
shared case, and did not have the static pieces that non-macCatalyst
targets are doing.
Try to match as much as possible the non-macCatalyst variables and
structure and allow macCatalyst targets to support static Swift targets.
This is important for the `Cxx.swiftmodule` and `CxxStdlib.swiftmodule`,
since they are only static, and the previous code skipped creating those
files since https://github.com/swiftlang/swift/pull/74994
