nvi2: Add locale modifications

nvi2: Add locale modifications

The following required modification:
  - zh_Hans_CN locales
  - renaming all missing extern files (name pollution) [1]
  - Added missing timespec header inclusion
  - change location of missing version.h [2]
  - SLIST_FOREACH_SAFE => SLIST_FOREACH_MUTABLE

[1] There were four separate extern.h files, all were missing from vendor
    branch.  They copied from FreeBSD and put at /usr.bin/vi
[2] The version.h header was also missing from vendor branch, so the
    relative path was removed.  It is now at /usr.bin/vi