It turns out there are valid usecases for exposing a standalone
objc-metaclass symbols and tbd files must encode it correctly.
resolves: rdar://118499886
Decls with a package access level are currently set to public SIL
linkages. This limits the ability to have more fine-grained control
and optimize around resilience and serialization.
This PR introduces a separate SIL linkage and FormalLinkage for
package decls, pipes them down to IRGen, and updates linkage checks
at call sites to include package linkage.
Resolves rdar://121409846
TBD files contain a section reserved for obj-c classes. Previously,
TBDGen was adding symbols with this + normal globals with objc class
prefixes. This patch removes the extra globals being added.
This also accounts for this behavior for `validate-tbd-against-ir`
checking.
Resolves: rdar://101442087
