why robust --prefix=/any install is important

[Yotam Medini <yotam_medini fastmail fm>]

Recently, I have tried installing:
   glib-2.3.0 + pango-1.3.0 + gtk+-2.3.0
(on my Gnu/Linux/Gentoo-1.4.2.0). Since I use my box
not just for trying out new Gtk+ versions, I wanted to ensure 
not to touch the working version of glib+Pango+Gtk I have.

So I tried building and installing - not as user='root',
and using --prefix=/home/local.
Alas, after successfully hacking glib+Pango build, 
with Gtk+ build, I encountered  problems
(See:
  http://mail.gnome.org/archives/gtk-devel-list/2003-November/msg00105.html )
that I did not have the time to deal with.

I really wanted to try the bidi-layout of the latest Pango, and may
be, if I could, help in debugging. But it's just too time consuming to
overcome configuration settings.

Now to my main message.

  The fact, that developing version of Gtk+ cannot be easily built
  without interfering with existing system, limits the debugging effort
  to those familiar with the details of build configuration.

regards -- yotam