Merge branch 'jk/big-and-future-archive-tar'

"git archive" learned to handle files that are larger than 8GB and
commits far in the future than expressible by the traditional US-TAR
format.

* jk/big-and-future-archive-tar:
  archive-tar: drop return value
  archive-tar: write extended headers for far-future mtime
  archive-tar: write extended headers for file sizes >= 8GB
  t5000: test tar files that overflow ustar headers
  t9300: factor out portable "head -c" replacement

diff --cc t/t9300-fast-import.sh
Simple merge