configure: add --without-libarchive option

configure: add --without-libarchive option

Teach configure the --without-libarchive option, which forcibly
disables use of the libarchive library.

The option --with-libarchive=direct will disable the use of dlopen,
and will link mke2fs with -larchive directly.  This doesn't work when
building mke2f.static, since -larchive has a large number of
depedencies, and even "pkgconf --libs --static libarchive" doesn't
provide all of the appropriate library dependencies.  :-(

Signed-off-by: Theodore Ts'o <tytso@mit.edu>