some package (alpine-baselayout) needs to create /usr/local/bin etc.

POSIX only requires that filedesriptors 0-9 are available for shell
redirections.

was totally broke.

This reverts commit e045c451.

we depend on curl instead

use the abuild-sudo tool instead

fixes #951

mini sudo that checks if user is in "abuild" group and allows it to
run apk, adduser adn addgroup as root

ref #951

fixes #955

For a second, indented message line.

We need locking Since the build servers use a shared download dir
and multiple vservers might want download same file at same time.

fixes #873

So we can set pkgname if it differs from download archive name

curl does not fail by default. it downloads the 404 error page instead
so we need add -f option to curl.

Not been used for ages.

fixes #871