It's been a given that any stage2 is propagator-based
but that's not neccessarily so; the "run X as PID 1"
sort of contest has sparkled interest in some others.

This change is done to reduce ambiguity in some cases;
the previous intention has been to ease navigation when
staying in a particular directory, now it's been changed
in favour of convenient toplevel `git grep' in fact.

Both variants have their pros and cons, I just find myself
leaning to this one by now hence the commit.  Feel free to
provide constructive criticism :)

Some path-related bitrot has also been fixed while at that.

The initial approach required some quite involved postprocessing
as described in http://www.altlinux.org/UEFI#HOWTO; after having
ironed out the kinks so that initial EFI support could be merged
into mkimage proper we're better off just using it, eh?

The issue actually hit image.in/Makefile: "metadata" target
in features.in/metadata/lib/50-metadata.mk wasn't reached
even if features.in/build-distro/lib/90-build-distro.mk
would ACK that the "whatever" actions included "metadata";
thus Metadata/pkg-groups.tar wasn't created and the installer
silently failed to install the .base system.

Let's armour the rest of the cases where the order of inclusion
might be important as well.

From now on, subprofiles can include the lib/*.mk
brought in by features just like image.in/ long did.

The existing implementation would handle kernel differences
just fine but a bit too automatically: if it sees xz support,
that's what will end up being used (and if there's -Xbcj binary
compression filter available for the target platform, it will
be applied unequivocally either).

It's perfectly suitabe for getting fine-tuned release images
but is also a bit too resource-consuming while developing the
image configuration which has no business with its compression.

The one and only knob is SQUASHFS (see doc/variables.txt);
to give an idea of the differences, here are some numbers
for a mostly-binary (43% as per 99-elf-stats) webkiosk livecd
and a rather less so (18%) flightgear one on a dual quad-core
X5570 node (each mksquashfs run used up all the cores):

SQUASHFS | live-webkiosk.iso | live-flightgear.iso
---------+-------------------+---------------------
fast     | 3:30 / 130M       | 5:11 / 852M
normal * | 3:37 / 100M       | 5:35 / 688M
tight    | 3:50 / 98M        | 6:47 / 683M

Thus if the knob isn't fiddled with, the defaults will allow
for a reasonably fast build of a pretty slim image; if one is
building a release or if a particular image is very sensitive
being close to the media capacity then just add SQUASHFS=tight
and see it a percent or two down on size.

Please note that lzo/gzip-compressed images are also quicker
to uncompress thus further helping with test iterations.

Thanks to led@ and glebfm@ for helpful hints and questions.

Referring to install2 subprofile after it got generalized
and renamed to stage2 is an omission, better fix it late
than never.

Avoid extra files where a variable would suffice; and use
the more specific "syslinux.list" rather than a "files.list".

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.

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.

It was clear that "common" isn't very apt for packages that
will get *everywhere*, and became apparent when the need for
a "base+live packages" variable arrived with powerbutton feature.

So:
- the former COMMON_PACKAGES are now SYSTEM_PACKAGES;
- COMMON_PACKAGES act as "BASE+LIVE_PACKAGES".

Note that SYSTEM_PACKAGES also got factored out from stage2 based
features into stage2 subprofile itself; cleanups were due as well.

squashcfk.mk is not to be attempted to copy unconditionally,
if we've got no kernel for stage2 there's no data (and hook)
to create it there

- introduced generic stage2 subprofile (non-standalone)
- ported installer and rescue over to stage2/{install2,rescue}
- initial stage2/live (needs more work for sure)
- use make-initrd-propagator
- updated and somewhat extended doc/

NB: mind #26133, #26134

s,INSTALLER_KFLAVOUR,STAGE1_KFLAVOUR,g
s,INSTALLER_KMODULES,STAGE1_KMODULES,g

install2 isn't the only livecd around;
so far all of these share the same kernel
in m-p-d, and we'd rather need two+ kernels
with dual-arch media or so; let's not complicate
things too much at this point

make CLEAN=1 will prune workdirs after packing their results,
so disk (or preferably tmpfs) usage will be lower

All the three scripts depend on installer kernel presence in fact.
When live/rescue are in place, these should be adjusted correspondingly,
probably by moving them to some commonly used intermediate place.

Changed stage1 banner too.

This looks a bit weird (two subprofiles become a bit more
tightly coupled) but in fact install2 does depend on stage1,
and if stage1 doesn't create squashcfg.mk then install2 is
just fine with defaults (provided they fit the installer kernel
used).  A proper mkimage test infrastructure might be handy though.

Also there:
- 01-initfs: partial cleanup (bootsplash is obsolete anyways)
- regarding 03-test-kernel's errorlevel test:
  if 0, 1 and 2 need to be distinguished, "!" MUST NOT be used
  as it negates so that 0 becomes 1 and the rest becomes 0

The problem rarely manifested itself on 8-way server
in the form of attempt to copy ./syslinux while it
wasn't there yet.  The proper fix should include
interdependencies but this kluge works either;
didn't observe this with other subprofiles.

Thanks go to lakostis@ (see #18047) for all the aic94xx reminders
and the final testing of the proposed image.

- image.in/functions.mk: rework kpackage()
  + it takes two arguments explicitly now: this adds some noise
    for "generic" invocations but is rather less messy with recently
    introduced STAGE1_KFLAVOUR (which in its turn is rather cleaner
    than messing with KFLAVOURS, especially since soemthing changed
    in presumably apt and we can't rely on kernel packages being
    installed in the order formed).
- BUILDDIR/DEBUG related fixes
  + Makefile: BUILDDIR initialization moved to distro.mk
- build.log += git info

Renamed server-light.iso into server-ovz.iso to avoid brand dilution
and confusion (rider@'s server-light rather favours kvm, anyways).

Introduced KDEFAULT: a reliable default kernel chooser knob
since apt's regex ordering proved pretty unreliable.
Spelling things explicitly is better anyways.

SYSLINUX related features undergone pretty major rewrite
(that includes syslinux, hdt and memtest).

The problem to tackle was features.in/syslinux/generate.mk
assuming syslinux and pciids available in build *host* system;
this well might not be the case (or worse yet, those can be
just different).  So now we're a bit less elegant and a bit
more enterprise, stuffing things into chroot and working there.

Bunch of other fixes along the road, including ; to name a few:
- fixed memtest entry (overlooked while renaming SYSLINUX_ITEMS)
- new and shiny doc/CodingStyle
- gfxboot, stage1 target chain, hdt tweaks
- distro.mk rehashed
- README++
- TODO: dropped (integer overflow anyways)
  + actually moved off-tree to reduce commit spam
- s,\.config\.mk,distcfg.mk,g
- doc/profiles.mk.sample: sample ~/.mkimage/profiles.mk
- ...and assorted fixups/additions

Sorry for convoluted commit, this would have been pretty hard to
rework into some really readable shape (and you might be interested
in the original repo's history horrors then, anyways).

- more thorough build stages inline doc
- quieter BUILDDIR instantiation
- branding-altlinux-sisyphus by default
- prettify installer selection somewhat
- mkimage #24669 fixed upstream
- sub.in/stage1/modules: +drm (as in m-p-d, for KMS)
- tags2lists: generalize a bit

- drop hardwired kernel flavour from pkglists
- today's std-ng lacks aufs, let's switch to un-def
- second assault at KERNEL_PACKAGES_REGEXP
- re-introduced kpackages (builds ok)

PS: base lists: switch to grub, add udev, cleanup

A major change in approach largely thanks to discussions
with Alexey Cheusov but also well aligned with my own findings:
autoconf doesn't let the variables to form an inheritance.

And data flow described at http://www.altlinux.org/WhiteLabel
(which in its turn was born thanks to Gavin Henrick of Diva Telecom
and to Alexander Bokovoy of SaM-Solutions) is really dependent on
the existence of such an inheritance.

Also:
- distro.mk += try()
- "hide" special targets
- fixed wrt distro/.{base,init,metaconf}, thx gns@
- README updates
  + added metaconf.mk
  + clarifications
- updated pci.ids location for hdt

Also included:
- reworked syslinux feature inclusion
- syslinux: s/textprompt/prompt/
- README++

- get rid of $dest
- work on features.in/syslinux
- README++

- set(), add(), log()
  + special thanks to rider@ for log format feedback
- simple debug facility
- builds, installs and runs... again

- syslinux: menu.c32 works
- features: initial draft
  + memtest
- mv pkg/ pkg.in/
  + server-base: include openssh-blacklist by default
- mv isodata/ copy/
- README: changed to utf8, added an URL