Used this feature to add x86_64 unwind information.

Use it to add a 256 byte block around current program counter.

dbghelp: Add our own thread data gathering struct for minidump internals instead on relying on SYSTEM_PROCESS_INFO.

'Unicode' and 'UTF-8' are used as is in Japanese (with thanks to Akihiro Sagawa).

It can be smaller than the number of columns found in the table meta data.