Formatting.
Add constant defines for gnu pubnames and gnu pubtypes - they're used
for the gdb index as the names convey.
Add the gnu pubnames and pubtypes sections to the mc object file
handling.
Rename for consistency.
Always add global names. We're adding them in the rest of the code
as well as types.

No functional change as they're not emitted unless the option
is true anyhow.