There are situations where you want to build against a libc that is out
of tree or that is not the system libc (Or for cross build scenarios).
This is a change for passing the -sdk and include paths for things like
this.
This allows the conversion of the Windows `BOOL` type to be converted to
`Bool` implicitly. The implicit bridging allows for a more ergonomic
use of the native Windows APIs in Swift.
Due to the ambiguity between the Objective C `BOOL` and the Windows
`BOOL`, we must manually map the `BOOL` type to the appropriate type.
This required lifting the mapping entry for `ObjCBool` from the mapped
types XMACRO definition into the inline definition in the importer.
Take the opportunity to simplify the mapping code.
Adjust the standard library usage of the `BOOL` type which is now
eclipsed by the new `WindowsBool` type, preferring to use `Bool`
whenever possible.
Thanks to Jordan Rose for the suggestion to do this and a couple of
hints along the way.
Magic symbols of the form $ld$install_name$os9.0$@rpath/libswiftCore.dylib tell the linker to use that install name when targeting that OS version. Use these symbols to specify an @rpath install name for all back-deployment libraries when targeting watchOS 2.0-5.1, iOS 7.0-12.1, and macOS 10.9-10.14.
rdar://problem/45027809
Use `ThreadHandle(bitPattern:)` rather than `unsafeBitCast` for the
conversion of the `uintptr_t` to the `HANDLE`. Convert a variable from
`var` to `let` binding.
The recent changes to the UnsafemutablePointer prevented the "abuse" of
the type for casting. Switch to `unsafeBitCast`. This should repair
the Windows build.
This is in preparation to make the code here more target agnostic for
porting to the Windows threading primitives. This is used pretty
extensively in the tests, so disabling tests would lose a chunk of
coverage.
