first pass at (rdi -> loose rdim) path, used in (rdi * ... * rdi) -> rdi joining in radbin; plug in regular conversion path before voff -> line & breakpad paths in radbin, such that PDBs, DWARFs, RDIs, etc. can be used as input; fix up voff -> line path to plug into regular output systems; remove String8 union thing - three reasons: (a) it was only ever introduced for convenience in Linux layers, so let's just keep zero-terminated Linux nonsense in Linux land, (b) it was just alternate syntax for a cast, so let's just cast, (c) it was misleading - 'cstr' implies null-termination, which String8 of course doesn't guarantee. this led to some misuses, where .cstr was trusted to be zero-terminated, when that was not necessarily true (semaphore opening).

src/rdi_from_pdb/rdi_from_pdb.c

@@ -1208,7 +1208,6 @@ p2r_convert(Arena *arena, P2R_ConvertParams *params)
     lane_sync_u64(&units_first_inline_site_line_tables, 0);
     RDIM_Unit *units = all_units_ptr->first ? all_units_ptr->first->v : 0;
     U64 units_count = all_units_ptr->first ? all_units_ptr->first->count : 0;
-    Assert(units_count == comp_units->count);
     
     //- rjf: do per-lane work
     if(params->subset_flags & (RDIM_SubsetFlag_Units|