Also if --purge is specified delete all uninstalled packages.
Fixes #2889

the dynamic applet registration never worked with PIE, and as
a temporary hack -nopie was added to default link flags in 2008.

this commit reworks the applet registration mechanism to something
that is compatible with PIE, and removes the hack. finally!

Simply print the default arch and exit.
This is so scripts don't need to parse the output of -V.

stdout is the proper place for it. this also fixes the progress
bar in musl, which seems to not support using line buffering for
stderr.

to not run any per-package scripts. useful for managing buildroot
when cross-compiling.

Acked-by: Natanael Copa <ncopa@alpinelinux.org>

Otherwise we cannot override with --no-progress

make cache a special kind of repository, and automatically cache
special packages (virtual packages, or ones installed from command
line). add test cases for handling virtual packages. fixes #1617.

also merge the expected output to the *.test files.

In case someone prefers extra quesions while running apk in a
terminal. The file is always from the real root; not from --root
so that we will not accidentally enable interactive mode when in
initramfs bootstrap.

Use it to avoid self-upgrade loops in case something fails during
the initial upgrade attempt.

 * fixup the help messages to align up properly
 * refresh screen width on SIGWINCH

This is so we can do x86 --root installs on x86_64 hosts.

Using --arch without --root can make great damage so we only enable it
if --root is used.

 * make it as wide as the screen
 * make sure it's drawn after package change
 * and draw it using ansi escapes in line buffered stderr

and make the progress bar disappear on regular runs too.

Also re-exec's apk-tools to perform rest of the upgrade using
the new apk-tools. This allows handling of new apk-tools features
properly. Fixes #140.

 - implement a hash table for commonly shared fields such as
   license, version and architecture
 - use macroes to print blobs or pkgname-pkgver strings
 - fix some old cruft

Otherwise we end up using wrong uid/gid mappings when doing install
to alternate system root. Fixes #434.

We want minimal static build. And this now also breaks with our openssl
since it tries to automatically dlopen some of the engine modules.

Take the uid/gid from passwd and group.