- multi-target, multi-arch, single-job builds

doc/variables.txt was missing the already-existing BUILDLOG
variable description, and ARCHES got added during multi-target
toplevel rewrite.  Other minor fixes come as appropriate.

The fallback case of building in a brother directory moved
from the last line of code to the first one becoming more
explicit along the way.

Support for slash-containing argument (being a tmpdir name
template prefix) has been added.

The former toplevel Makefile is now toplevel main.mk;
this change allows for multi-target, multi-arch processing
in the current toplevel Makefile.

As the "build" symlink semantics change quite considerably
when one is doing bulk builds (several pruned builddirs might
be useful for comparison), BUILDDIR is now much more likely
to be recreated: the cases when it will persist are when it's
either a single-image build or when the prefix hasn't changed.

There are some more or less subtle bugfixes and enhancements
all over the map as well.

Done within 20111230..20120102 timeframe, actually...

First, let's not do rsync --delete on an unverified target dir
again: the lesson was learned during a subway hacking session
and I must say that SSDs are frightening fast (even if it was
more than a second to realize what happens and terminate the
extermination before it got /home, thanks xterm).

Second, let's use a variable for common name and make's own
realpath function instead of external binary.

At least it shouldn't bail out when the anticipated file
just isn't there...

Initial openSUSE package base taming effort has shown that
relatively few things should be fixed; subst has been generalized
as -i option to sed(1) since its introduction, so let's just fix it.

*_PACKAGES and *_LISTS shouldn't inflict copypasted blocks;
we can iterate over these just fine.

NB: dump-*, not dump_*, due to namespace pollution hurting
debug target if done the latter way (in case someone misses
the morning tea as wel).

As current devmapper doesn't allow for simultaneous
mounts of virtually the same device by different names
(signalled by "Device or resource busy" when trying to
e.g. mount /dev/sda2 but with /dev/evms/sda2 being just
fine), EVMS triggering such behaviour but rarely needed
should be avoided altogether until a hook to disable it
is in place.

Fixed up the remnants of the early style mix
to correspond to the proposed doc/style.txt;
the rationale being that

	if [ ... ]; then
		...
		...
	fi

is the more readable construct among itself,

	if test ...; then
		...
		...
	fi

and

	[ ... ] && {
		...
		...
	}

due to the condition being more distinguishable
when bracketed and the body more apparent as the
one inside "if" and not any other block; the less
obvious difference is that the final construct of
the latter form is prone to the whole script exit
status being non-zero if the condition isn't met.

- it wasn't firmware-carl9170 but firmware-carl9170-1.9.4
- firmware-linux Obsoletes: firmware-iwl* since 20110520-alt1

screen(1) is definitely the part of a server;
tmux(1) can also be installed of course.

Thanks vvk@ (#15887).

- THE_{KMODULES,PACKAGES,LISTS,GROUPS}
- incremental development, refactoring and bugfixing

Let's prepare some moderately sane base for future desktop
installers, it's not only icewm around anymore.

As 0.4.0 just came out and seems to be quite interesting,
why not add it to the collection? :)

Package base advice is welcome, of course.

Some parts of *image* configuration started slipping down
into the *feature* configuration, and that was wrong; fixed.

Also introduced proper use/live/x11 (via use/x11/xorg with added
wacom support for the sake of #26723/#26724) and rebased the
pre-existing descendants onto it.

As too many things started duplicating between distros proper
and (e.g. corresponding) LiveCDs, it became apparent that a class
of entities which end up working for THE_USER (not a sysadmin,
and not a developer, just a Linux user) is in need.

So THE_KMODULES will power installed basesystem and live image,
while THE_PACKAGES, THE_LISTS and THE_GROUPS will participate
in building those.

- parameter order fixed to "simple first, then those with args"
  and documented as the preferred one (might be debatable, okay)
- added "lowmem" to live so it avoids a ramdisk but works off media
  (it's a knob for propagator)
- added "fastboot" everywhere (but failsafe install) to make use
  of Linux 2.6.29+ async controller initialization
- every snippet got a trailing newline so that isolinux.cfg is readable

And a fancy makefile to check for shortcut dups!

Some more filesystem related utilities inspired by PLD rescue
are due indeed; but ntfsprogs are obsoleted by ntfs-3g, in fact.

iotop and iperf were suggested by stalker@.

Several targets were used in a duplicated way
that made no harm but no sense either.

"sub/stage2/live" might seem a bit cryptic and not readily
traceable, so let's expand on explanations accordingly.

Here we go with postprocessing priorities along the way
as ISO hybridization has to occur before implanting
final MD5 sum (which must happen earlier than e.g. some
external MD5SUM file generation).

Unfortunately proper dependencies aren't applicable here
(though I'd like to be proved wrong on this one).

Please note that this needs propagator > 20101130-alt9
for automatic mode to work (has also been worked around
in gfxboot case with design-bootloader-source-6.0-alt1).

Thanks rom_as@ for asking about the hybrid image status
and helping out with testing.

This one used to use LIVE_MAIN_GROUPS which seems to be
overlooked substitution artifact from walking over
GLOBAL_PKG_GROUPS and GLOBAL_LIVE_PKG_GROUPS of m-p-d...
(not that LIVE_GROUPS are defined anywhere yet)

$(SHORTEN) is better in the midst of the pipe
so that greps are terminal and can sense the tty
(or the lack thereof in case we're logging further).

Actually there's an added duplication in the form of the
test that was previously missing in pkg.in/lists/Makefile
-- that has to be done properly when it's clear how.

This fully omits pkg/lists/.base generation in environments
that won't make use of it.

The outmost shell loop got replaced with a (hidden) bunch
of targets -- it's somewhat controversial as the inner loops
are still there (but at least don't wrap around my SXGA+).

Full targetization might be beneficial in terms of parallelism
achievable *but* that would ruin git history being generated,
and building a distro configuration takes a few seconds at most.

(upon reading http://stackoverflow.com/questions/5414418/)

The idea is to check:
- the reachability of every target
  used to build the image in question;
- the availability of all the package lists
  and subsequently packages for that image;
- the lack of "dangling" intermediate targets,
  features, pkglists, hooks etc.

So far only the first step is implemented --
it's easy and somewhat helpful already for
  make CHECK=1 all

- generic VE archive type (added cpio and xz either)
- minor additions/fixes

The bin/pkgdups.sh script comes from m-p-d in considerably optimized
form and is to be used with the pkglist files of interest passed
as its arguments to produce a "hall of duplicates" among those.

The tagged lists received some updates along the rescue image lines,
most of those are actually inspired by http://rescuecd.pld-linux.org/
and to lesser extent a few articles on rescue/recovery/forensics
software -- so some newcomers are even employed already.

Just a hook to export alt-gpgkeys pubring data.

This sketch quickly pulls virtualbox guest additions in
the installed system; should probably be extended with
other VM support...

New stuff:
* distro/live-icewm -- basic icewm livecd with autologin;
* distro/live-rescue -- yet another gparted^Wrescue CD.

A better part of base+rescue tagged pkglist split off into
extra+rescue where the content belongs.

Thanks ruslandh@ for proposing to do a graphical rescue with some
particular tools (albeit qt4-fsarchiver clearly needs more work).

use/live/autologin target tries hard to configure any available
autologin means, including a dedicated package and a few DMs.

Thanks gns@ as liveflash.eeepc got robbed somewhat.

distro/live-builder target used to employ a few duplicated
packages that might make it to a list but as the list would
have only a single user so far these were moved to a target-
specific variable (hm, weird but "private" modifier broke).

COMMON_PACKAGES make it into basesystem like BASE_PACKAGES,
not just into RPMS.main like MAIN_PACKAGES.

It's official now.

Actually this is the proper rewrite that was looming ever since
tgz support was introduced: there are multiple archive formats
supported by mkimage, and there are multiple compression methods
available as well.

So the bullet got bitten yet again along with the "goal parser"
which should be more straightforward by now.

Thanks dkr@ and mithraen@ for the inspiration of this evening.