It appears that when the subshell has a ||, the 'set -e' within
subshell gets invalidated.

This will work as expected:

 ( set -e; false; echo "should not get here" )

While this will not work as expected:

 ( set -e; false; echo "should not get here" ) || false

We resolve it by using $? to detect the status of subshell. We also let
the exitcode indicate how many packages that failed.

While here we also refactor it so most of the loop happens within the
subshell. This lets us set (or increase) rc variable once, and it
reduces number of forks which gives slightly better performance.

We actually want be able to re-run abump without needing reset the
pkgver in case we had to fix things.

This reverts commit 8198ded8.

Conflicts:
	abump.in

Otherwise abuild-sign will end with error

This permits introducing branch-specific modifications to abuild.conf settings.
Any settings there override /etc/abuild.conf and $HOME/.abuild/abuild.conf.

* includes renaming pkgname, pkgver

* make vars local
* refactor calculation of default_name
* make non_interactive=1
* tweak error message
* tweak sed command

as discussed in http://lists.alpinelinux.org/alpine-devel/3122.html

Also remove incomplete efforts at listing "Depends on: ..."

as discussed in http://lists.alpinelinux.org/alpine-devel/3122.html

introduce post_unpack that by default will search for config.sub and
config.guess and replace those if found.

we ship our own version of those files

check for pkguser, pkggroup, subpackage