pkg_extract(): Add support for pax and add new methods

Even though we had a portable extraction method for tarballs, this slowed
down the extraction immensely. I have added 2 new methods for tarball
extraction so that we have faster extraction speeds based on the system
tar implementation. Here are the options with the order of preference:

- pax: Although an uncommon program, pax is defined by POSIX, and
  supports regular expressions, meaning that we can 'strip' components.
  This is slightly faster than bsdtar and GNU tar.
- bsdtar/gnutar: We simply use '--strip-components 1' for these tar
  implementations.
- tar: This is the portable method we had been using for a while, it's
  good, gets the job done, but it is slower.

Here is also a little benchmarking I did by extracting the Linux tarball
for 10 times per method.

    tarball=$CPT_CACHE/sources/linux-headers/linux-5.10.12.tar.xz
    for extract in pax bsdtar tar; do
    time sh -c ". cpt-lib
                extract=$extract
                for i in \$(seq 10); do
                mkdir -p hdr; cd hdr;
                tar_extract \"$tarball\"; cd ..;
                rm -rf hdr
                done"
    done

This yields the following output, methods are as ordered above:

sh -c   75.21s user 11.11s system 115% cpu 1:14.90 total
sh -c   78.68s user 14.64s system 124% cpu 1:15.15 total
sh -c   99.88s user 69.99s system 119% cpu 2:21.70 total

FossilOrigin-Name: 45e3a9a03e7eff9b30b0e911d68d44068e8681ebf4501f271c8a686118f29243

0 files changed, 0 insertions, 0 deletions