This eliminates UnicodeData.h from the public SwiftShims. A small
part of it remains as a private header, but everything else moves
into `@_extern(c)`.
This replaces a number of `#include`-s like this:
```
#include "../../../stdlib/public/SwiftShims/Visibility.h"
```
with this:
```
#include "swift/shims/Visibility.h"
```
This is needed to allow SwiftCompilerSources to use C++ headers which include SwiftShims headers. Currently trying to do that results in errors:
```
swift/swift/include/swift/Demangling/../../../stdlib/public/SwiftShims/module.modulemap:1:8: error: redefinition of module 'SwiftShims'
module SwiftShims {
^
Builds.noindex/swift/swift/bootstrapping0/lib/swift/shims/module.modulemap:1:8: note: previously defined here
module SwiftShims {
^
```
This happens because the headers in both the source dir and the build dir refer to SwiftShims headers by relative path, and both the source root and the build root contain SwiftShims headers (which are equivalent, but since they are located in different dirs, Clang treats them as different modules).
* Generate Unicode data for Scalar Binary Properties
* Use native scalar binary property lookup
* Add _BinaryProperties to Scalar Properties
narrow access control
* Upgrade the notice to a warning in UnicodeScalarProperties
* Implement GraphemeWalker that does native grapheme breaking
* Bridged strings use native grapheme breaking for forward strides
* Implement bidirectional native grapheme breaking for native and foreign strings
* Remove ICU's grapheme breaking support
* Use UnicodeScalarView to implement GraphemeWalker
use an Iterator approach
remove Iterator conformance
* Incorporate Michael's feedback
more comments addressed
fix crlf bug
* Try bringing back some old fast paths
* Parameterize nextBoundary and previousBoundary
Parameterize nextBoundary and previousBoundary
* Implement Michael's suggestions
Alejandro Alonso
Doug Gregor
Alexander Cyon
David Smith
L-j-h-c
Egor Zhdan