Availability macros passed via the frontend flag -define-availability
should be accepted by @_originallyDefinedIn where they behave as they do
in @available.
rdar://72354787
This affects module interfaces, interface generation in sourcekitd, and
diagnostics. Also fixes a fixit that was assuming the 'OSX' spelling when
computing the source range to replace.
Resolves rdar://problem/64667960
We need this attribute to teach compiler to use a different name from the current
module name when generating runtime symbol names for a declaration. This is to serve
the workflow of refactoring a symbol from one library to another without breaking the existing
ABI.
This patch focuses on parsing and serializing the attribute, so @_originallyDefinedIn
will show up in AST, swiftinterface files and swiftmodule files.
rdar://55268186
