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 --combined t/t9300-fast-import.sh
index 74d740de41bbd489dd0ce9fb811f9ea1c08b248c,38a06aaafc72a337b1d25c9f18715dec4b2208f4..2e0ba3ebd8ab3273144743dc38675e2b5d429ea1
--- 1/t/t9300-fast-import.sh
--- 2/t/t9300-fast-import.sh
+++ b/t/t9300-fast-import.sh
@@@ -7,23 -7,6 +7,6 @@@ test_description='test git fast-import 
  . ./test-lib.sh
  . "$TEST_DIRECTORY"/diff-lib.sh ;# test-lib chdir's into trash
  
- # Print $1 bytes from stdin to stdout.
- #
- # This could be written as "head -c $1", but IRIX "head" does not
- # support the -c option.
- head_c () {
-       perl -e '
-               my $len = $ARGV[1];
-               while ($len > 0) {
-                       my $s;
-                       my $nread = sysread(STDIN, $s, $len);
-                       die "cannot read: $!" unless defined($nread);
-                       print $s;
-                       $len -= $nread;
-               }
-       ' - "$1"
- }
- 
  verify_packs () {
        for p in .git/objects/pack/*.pack
        do
@@@ -52,7 -35,6 +35,7 @@@ echo "$@"
  ###
  
  test_expect_success 'empty stream succeeds' '
 +      git config fastimport.unpackLimit 0 &&
        git fast-import </dev/null
  '
  
@@@ -2481,7 -2463,7 +2464,7 @@@ test_expect_success PIPE 'R: copy usin
  
                read blob_id type size <&3 &&
                echo "$blob_id $type $size" >response &&
-               head_c $size >blob <&3 &&
+               test_copy_bytes $size >blob <&3 &&
                read newline <&3 &&
  
                cat <<-EOF &&
@@@ -2524,7 -2506,7 +2507,7 @@@ test_expect_success PIPE 'R: print blo
                EOF
  
                read blob_id type size <&3 &&
-               head_c $size >actual <&3 &&
+               test_copy_bytes $size >actual <&3 &&
                read newline <&3 &&
  
                echo
@@@ -2559,7 -2541,7 +2542,7 @@@ test_expect_success PIPE 'R: print stag
                echo "cat-blob $to_get" &&
  
                read blob_id type size <&3 &&
-               head_c $size >actual <&3 &&
+               test_copy_bytes $size >actual <&3 &&
                read newline <&3 &&
  
                echo deleteall
@@@ -2691,7 -2673,6 +2674,7 @@@ test_expect_success 'R: blob bigger tha
        echo >>input &&
  
        test_create_repo R &&
 +      git --git-dir=R/.git config fastimport.unpackLimit 0 &&
        git --git-dir=R/.git fast-import --big-file-threshold=1 <input
  '