This patch adds general support for DWARFv5 index writing.
In particular, this means only allowing inputs with one version,
either DWARFv5 or DWARFv4.
This patch adds the .debug_macro section as an example,
but the DWARFv5 type support and loc and rangelists are still
missing (and upcoming).
Reviewed By: dblaikie
Differential Revision: https://reviews.llvm.org/D102315
Kim-Anh Tran