Serialize the `-public-autolink-library <name>` option to the
moduleinterface file because it can affect the LINK_LIBRARY entries in a
swiftmodule file. Without saving the option, the library won't be linked
when a module compiled from the moduleinterface is used.
This change marks the `-public-autolink-library` option as a module
interface option and reads it when building a swiftmodule by module
loader.
