K2MetadataCompiler is a compiler facade similar to K2JVMCompiler and
K2JSCompiler and it produces .kotlin_metadata files. Each .kotlin_metadata file
contains the binary data which is a serialized BuiltIns protobuf message.
There's no 'kotlinc-***' script yet though, so to run this compiler currently
invoke this:
KOTLIN_COMPILER=org.jetbrains.kotlin.cli.metadata.K2MetadataCompiler kotlinc
Alexander Udalov
ec03c6decb