of libarchive being used. I've been taking advantage of this
with a recent round of updates to libarchive_test so that it
can test older and newer versions of the library.
Approved by: re (Ken Smith)
a vanilla 2-clause BSD license, but somehow some confusing
extra verbage get copied from somewhere.
Also, update the copyright dates to 2007 for all of the files.
Prompted by: several questions about what those extra words really mean
wrap this within #if/#else/#endif so that it will only take effect once
ARCHIVE_API_VERSION is increased (which should happen on HEAD some time
between now and when RELENG_7 is branched).
