mkimage and hasher can make use of qemu to run
non-native binaries while working on the chroots;
thanks kas@, manowar@ and sbolshakov@ for implementing
this functionality as well as providing nice examples
through mkimage-profiles-arm and mkimage-profile-armrootfs.

This required the architecture check to be added since baking
a tarball with "arm" as its specified arch and x86_64 inside
isn't particularly good thing to let slip through; however
the implementation is quite fragile, bugreports and patches
are seriously welcome.

NB: APTCONF evaluation order between lazy make and nimble shell
turned out to be quite a delicate issue in this particular case.

- arm builds

The only thing to be fixed was setarch(8) symlinks assumption
that is correct for x86 but not for ARM.

There's also some hasher(7) setup to be done:

  mkdir -p ~/.hasher
  echo >> ~/.hasher/config <<-EOF
  def_target=arm
  #cache_dir=$HOME/tmp	# depends on RAM/storage configuration
  EOF

...and of course apt(8) should be properly set up too.

An example PoC build on a CM-A510 board (tmpfs):

  $ make BRANDING=altlinux-centaurus ve/bare.tar.gz
  ** ARCH: arm
  18:10:45 initializing BUILDDIR: build/
  18:10:45 preparing distro config: build/distcfg.mk
  18:10:46 starting image build: tail -f build/build.log
  18:14:49 done (4:02)
  ** image: $TMP/out/bare-20120706-arm.tar.gz [23M]

~/.mkimage/profiles.mk is useful but not requisite by any margin;
no need to make noise trying to make it either.

Whoops, an overlooked character didn't bring too many
things down but was a BUG indeed :-/

- simply fixes

It's not DHCP we're configuring but rather eth0.
(no need for trailing space either)

The very basic bitmap fonts that were left in back a year ago
aren't particularly modern (even if they are somewhat elegant
and resource sparing which was the goal at that time).

So let's allow for something slightly prettier,
like Croscore Arimo kindly prepared by Steve Matteson,
provided by Google, packaged by Fedora and imported by
Igor Vlasenko.

Here's the news item behind this commit:
http://lwn.net/Articles/502371/

As they say there's nothing more permanent
than a temporary... params.txt and pkglists.txt
were known as vars-build.txt and vars-conf.mk
in the midst of reworking, and part of that
tried to stick.

A few too many downstream makefiles employed the pattern
of "export GLOBAL_VAR := $(VAR)"; macroize that.

mkimage implementation requires that the variables
to be passed to the scripts are to be prefixed with
GLOBAL_ or INFO_ tags as appropriate; in this case
the upstream makefile didn't care to.

It's better to rather just move the raw image instead
of specifically converting it into the same, and there's
no need for qemu-img altogether then.

Let's drop the intermediate raw image after successful
conversion as well.

Use it only for gdm and lightdm and only if it is used
in a PAM config.

Setup network settings:
1. Init /etc/hosts with "127.0.0.1 localhost"
2. Set hostname, domainname
3. Set defaults for NetworkManager or
   attempt to autoconfigure eth0 by etcnet.

Based on init3-network script from m-p-d.

Set system time to local time.

- vm improvements and assorted tweaks/fixes

There's no reason to bail out if xdg-user-dirs control
facility is not available within the branch used.

Minor tweaks to toplevel docs as well as some doc/*.txt,
doc/variables.txt renamed to doc/params.txt, and a brand new
doc/pkglists.txt is added (thanks manowar@ for his considerations).

It's configured by plymouth feature when needed;
install2 bootargs support is generalized a bit
to become stage2 one as was intended anyways.

This one was requested by Andrew Churashev; please note
that the image in use must contain recent flash plugin
so that at least the already known vulnerabilities are
more or less plugged in it... and Sun Java plugin isn't
going to get secure either.

A virtual machine isn't very useful if there are no means
to access it; let's bring up the basic networking and provide
root SSH access via pre-existing public key.

As the remote access with known default credentials is roughly
equivalent to just lending one's VMs to anyone with network
access to it, the fallback root password is now exterminated;
you have to provide one (or a long enough random string
if you plan to use keys only, see e.g. apg utility).

There's no need to repeat the typical openssh-* triade
all over the place; those who need server and client
are better off pulling in "openssh" pkglist, and those
needing a particular package should specify it.

There's no need to disable console as it's emulated too,
and it still can be helpful or just convenient.

The "vm" name became a bit confusing with the introduction
of build-vm feature; let's call this one "vmguest" until we do
hierarchical (sub)features.

Finally tired of expr(1) quirks,
and even ash(1) does $((arithmetic-expansion))!

It appears that reusing installer-feature-*-stage3 packages
is perfectly fine with VM images; these just need to be removed
after the package scripts they carry have worked out.

Raw disk images are convenient and universal
but there are custom formats like Qemu's qcow2
providing additional features, e.g. copy-on-write
or space savings.  All of this ultimately belongs
to mkimage but in the mean time has been implemented
here as well.

After we have built a bare virtual machine image successfully
some variations are due, and these are to be described here.

installer-feature-no-xconsole depends on stage2 bits and is
NOT intended for installed/live systems at all; let's move
to the proper stage3 based one.

Was mentioning REPORTS while the variable name is REPORT.

Don't allow systemd to set LANG for all processes.
See ALT#27408 for details.

Turn on xdg-user-dirs by default.

Workaround for ALT#13213.

$(IMAGE_NAME).$(IMAGE_TYPE) -> $(IMAGE_NAME)-latest-$(ARCH).$(IMAGE_TYPE)

Allow to put the log files and reports in a custom directory instead
of IMIGEDIR.