packages should never depend on themselves which does not make sense.
This may happen if main package depends on a subpackage, then the
subpackages will inherit the global depends and the subpackage ends up
depend on itself.

Fix abuild to avoid this.

The 'Compressing data' step takes a significant amount of time when
packaging software with huge binaries, like Kubernetes. This can
certainly be shortened using multithreaded compression, like 'pigz'.

Symbolic links might point to files outside of the chroot and
thus might delete files outside the chroot. This allows deletion
of arbitrary directories on the host from a malicious APKBUILD.

Following hard links shouldn't be a problem since hard links (usually)
cannot refer to directories and since remove(3) removes the link, not
the file it points to it shouldn't cause a problem.

I noticed this because alpine-baselayout creates /var/run as a symlink
to /run. Therefore causing /run to be deleted on the host when using
abuild-rmtemp which in turn causes a bunch of software to no longer
function properly (including OpenRC).

So we make sure chdir $builddir happens when it should.

Only run check in fakeroot if options="checkroot" is set. This makes
options="!checkroot" the default.

I expect most checks work as non-root, and if a testsuite requires root,
it will likely fail in fakeroot too. Fakeroot has also shown lower
performance for parallel builds.

instead of printing abuild version, print package version. This is to
avoid confuse the abuild version with the package version.