xlog.c timezone name size

On multibyte language locale environment of win32, size of %Z of localtime() function is bigger more then 12 bytes.

so, I suggest that change str_time() function in src/backend/access/transam/xlog.c (2765 line)

buf char array size must be at least 70 bytes (20 bytes = datetime, 50 bytes = tzname of depended local locale(?))

Current str_time() function do not return new line on korean language win32 environment.
It's same on CJK.