MFC r315636,315876,316095:
Sync libarchive with vendor

Vendor changes/bugfixes (FreeBSD-related):
r315636:
PR 867 (bsdcpio): show numeric uid/gid when names are not found
PR 870 (seekable zip): accept files with valid ZIP64 EOCD headers
PR 880 (pax): Fix handling of "size" pax header keyword
PR 887 (crypto): Discard 3072 bytes instead of 1024 of first keystream
OSS-Fuzz issue 806 (mtree): rework mtree_atol10 integer parser
Break ACL read/write code into platform-specific source files

r315876:
Store extended attributes with extattr_set_link() if no fd is provided
Add extended attribute tests to libarchive and bsdtar
Fix tar's test_option_acls
Support the UF_HIDDEN file flag

r316095:
Constify variables in several places
Unify platform ACL code in a single source file
Fix unused variable if compiling on FreeBSD without NFSv4 ACL support

Copy head (r256279) to stable/10 as part of the 10.0-RELEASE cycle.

Approved by: re (implicit)
Sponsored by: The FreeBSD Foundation

Update libarchive to 3.0.4

Update libarchive to 3.0.3

Some of new features:
- New readers: RAR, LHA/LZH, CAB reader, 7-Zip
- New writers: ISO9660, XAR
- Improvements to many formats, especially including ISO9660 and Zip
- Stackable write filters to write, e.g., tar.gz.uu in a single pass
- Exploit seekable input; new "seekable" Zip reader can exploit the Zip
Central Directory when it's available; the old "streamable" Zip reader
is still fully supported for cases where seeking is not possible.

Full release notes available at:
https://github.com/libarchive/libarchive/wiki/ReleaseNotes

Set svn:keywords to FreeBSD=%H for contrib/libarchive

MFC after: 2 weeks

Copy libarchive from vendor branch to contrib

MFC after: 2 weeks

Set svn:eol-style property to native for all text files in vendor/libarchive

Vendor import of libarchive (release/2.8, r3824)

Obtained from: http://libarchive.googlecode.com/svn/release/2.8