swift234

Name mangling: Add a "_Tt" prefix to all type names that are output in
the debug info, to aid the debugger in figuring out the implementation
language of a given type in multi-language environments.
FYI, where applicable, we also emit the
DW_AT_APPLE_runtime_class(DW_AT_lang_Swift) attribute.
The demangler accepts type names with the "_Tt" prefix without the --type
switch.

Swift SVN r6714