The legacy WebKit availability macros are verbose, confusing, and provide no benefit
over using the system availability macros directly. The original vision was that
they'd serve a cross-platform purpose but that never came to be.

Since WebKit1 is API on OS X but SPI on iOS, some indirection is still needed in the
availability macros to allow the headers to advertise the API as unavailable on OS X
without interfering with the ability to build on iOS. This is achieved by defining
WEBKIT-prefixed versions of the Foundation availability macros that are defined to
their NS-prefixed equivalents. The installed headers are post-processed to map these
macros back to their Foundation equivalents.

Part of <rdar://problem/15512304>.

Source/WebCore:

Reviewed by Sam Weinig.

* WebCore.xcodeproj/project.pbxproj:
* bindings/objc/WebKitAvailability.h: Added. This lives at the WebCore level since it
will be needed by the Objective-C DOM bindings.

Source/WebKit:

Reviewed by Sam Weinig.

* WebKit.xcodeproj/project.pbxproj: Change the Postprocess Headers build phase to
invoke mac/postprocess-headers.sh.

Source/WebKit/mac:

The OS X version used in the new availability macros is based on the mapping in
JavaScriptCore/WebKitAvailability.h.

Reviewed by Sam Weinig.

* Carbon/CarbonUtils.h:
* Carbon/HIWebView.h:
* MigrateHeaders.make: Migrate WebKitAvailability.h from WebCore as an API header.
* Plugins/WebPlugin.h:
* Plugins/WebPluginViewFactory.h:
* WebView/WebFrameLoadDelegate.h:
* WebView/WebResourceLoadDelegatePrivate.h:
* WebView/WebUIDelegate.h:
* postprocess-headers.sh: Added. Extracted from the Xcode project. Extended to map the
WEBKIT-prefixed macros to their NS-prefixed equivalents on OS X and to remove them on iOS.


git-svn-id: http://svn.webkit.org/repository/webkit/trunk@161332 268f45cc-cd09-0410-ab3c-d52691b4dbfc