[gentoo-desktop] Re: how to emerge gnome2.12

[Duncan]

Chris Smart posted <4348D8EA.4010403@××××××××××××.net>, excerpted below, 
on Sun, 09 Oct 2005 18:46:34 +1000:

> libertine wrote:
>
>> i want to know how to emerge gnome2.12
>> i heard it was heavy masked
>> who can tell me how to emerge it
>> thx
>
> Hi libertine,
>
> echo "gnome-base/gnome" >> /etc/portage/package.unmask
> would be a good start.
>
> Add "gtk gtk2 gnome" to your USE flags and try
> emerge -av gnome

Disclaimer:  Lest anyone be confused, I'm not a Gentoo dev, only a user,
tho I DO follow the postings to the dev list on a regular basis, the
better to keep informed of what's going on in my distribution of choice!
=8^)  Thus, I'm posting AS a user, tho a hopefully well informed one, and
anything I say below should be read with that in mind.

Note that setting those USE flags isn't necessary, and may or may not be
what's desired.  Also note that the gtk2 flag is deprecated, and the
meaning of the gtk USE flag has changed slightly, recently (altho there
are probably still a lot of old ebuilds in the tree using both flags in
the old sense).

USE flags turn on OPTIONAL features or support, not MANDATORY
dependencies, which are installed anyway if you emerge something that has
to have them.  Thus, emerging GNOME or KDE (or any of the other window
managers or environments) will cause X (defaulting to xorg) to be merged
as a dependency regardless of the setting of the X use flag, because it's
non-optional -- they don't work without it.

What the gnome and the gtk USE flags do, then is turn on optional support
for gtk and gnome where there's a choice of support or not, say for
console apps that have an optional X interface that happens to use the
Gimp toolkit (GTK) or GNOME.  In /most/ cases, if someone has GNOME (which
means GTK as well, since GTK is a non-optional dependency of GNOME)
merged, they will /want/ support for GTK/GNOME where it's optional as
well, and thus /want/ the USE flags turned on.  However, that isn't
/always/ the case, thus the USE flags, and the option.  

As an example, I have the links web browser compiled USE=-X, to turn off
the support for X in it, using /etc/portage/package.use, even tho I have
USE=X set in make.conf. The reason is that I use links as a text based
browser, and want to have it available even if X isn't working correctly.
If it is compiled with X support and the Xlibs cannot be found or are
hosed for whatever reason, it will refuse to load, as it has unresolved
symbols (I had this happen at one point).  Since I use Konqueror for most 
of my browsing when I'm in X anyway, and thus don't use links as a
graphical browser, only in text mode, I don't use the X support anyway,
and prefer to have links available even when X is hosed, so it's best for
me to merge links with USE=-X.  As mentioned, since I have USE=X set
globally in my make.conf, I use /etc/portage/package.use to set USE=-X for
links specifically.

The history behind the gtk/gtk2 USE flags is as follows.  When Gentoo
started, there was only the first version of gtk, now gtk1.  Thus, the gtk
USE flag.  Later, when GTK2 first came out, it wasn't considered entirely
stable, so the default was still to GTK1.  The gtk2 USE flag was added to
allow folks who wanted gtk2 instead of gtk1 support, where both were
offered, a change to specify that exactly, where both are supported,
prefer gtk2.  Of course, that was some time ago, and gtk2 has been stable
for a long time, now.

Unfortunately, the gtk2 USE flag has been a constant source of confusion,
since -gtk +gtk2 officially meant do NOT install gtk support of EITHER
variety if it's an option, but if gtk1 and gtk2 are both supported and ONE
is required, install gtk2 support, and that's rather unintuitive.  What
everybody EXPECTED it to mean, if they hadn't /very/ /carefully/ read the
USE flag documentation, was "Yes, give me gtk2 support, even where it's
optional, and no, I don't want gtk1 support."

Thus the recent change.  According to a notice recently on the dev list,
the gtk2 flag is now officially deprecated and isn't to be used in new
ebuilds (altho it continues to exist in many old ebuilds).  Instead, new
ebuilds are to use the gtk flag only, to mean "Yes, add optional support
for GTK of any version."  The version the ebuild actually uses, if both
version 1 and 2 are supported, will be up to the maintaining developer,
but will at this point normally be version 2 by default (altho properly,
the ebuild will test to see which is already merged and build for version
1 if that's all that's merged).  This also makes way for an eventual GTK
version 3, without confusion.  The ebuild maintainer will then ultimately
decide when gtk v3 support in the package in question, as well as gtk 3
itself, is stable enough to switch optional support to it by default. 
Until then, it would stay version 2 by default, even after version 3 comes
out.  

(Do note, however, that there are ways to specify your own defaults,
working around those portage would normally use, if desired.  This usually
means using the less well documented EXTRA_ECONF variable, to directly
specify a command line option portage should add to the configure command,
when it runs it.  Be careful with this, however, because as the devs like
to say, "If it breaks something, you get to keep the pieces!", meaning
they most likely won't support it.  Users who just want things to work can
use the defaults the devs consider safe, and then if it does break,
they'll have support.)

So...  anything still masked for testing is likely new enough the gtk USE
flag is all that would apply.  However, merging Gnome shouldn't require
any of the three USE flags, gtk, gtk2, gnome, be set, since those
dependencies are mandatory for parts of gnome.  Those USE flags will only
make a difference on packages that have optional gtk/gnome support.

-- 
Duncan - List replies preferred.   No HTML msgs.
"Every nonfree program has a lord, a master --
and if you use the program, he is your master."  Richard Stallman in
http://www.linuxdevcenter.com/pub/a/linux/2004/12/22/rms_interview.html


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