bug#30093: Installing python-ipython breaks Gnome on Fedora.

[Fis Trivial <ybbs.daans@hotmail.com>]

Maybe we can Maybe we can divide those environment variables into two types:
      1. Needed directly by human. For example the *PATH* environment, we use it
      	 to start whatever program from the shell.
      2. Environment variables only needed by programs. For examples, the
	 *PYTHONPATH*, or in this case *GI_TYPELIB_PATH*.

For _type 2_, we can try to wrap every program with a simple script, and
propagate all the needed environment variables from its dependencies to that
wrapping script. This should eliminate the need to put any of those environment
variables into ~/.guix-profile/etc/profile, guaranteeing the safety of these
variables.

But this method won't solve all the problems. For examples *XDG_DATA_DIRS* will
 be classified as one of variables that needed by human because we need to use
 it to find GUI programs with GUI shell, and it's also needed by some programs
(a script in this case):

> This sounds similar to the following bug:
>
> https://debbugs.gnu.org/cgi/bugreport.cgi?bug=26202
>
To mitigate the problem in above link, which is the problem introduced by
_type 1_ variables, maybe we can treat these environment variables differently.
When guix is updating it to a new value due to change of profile, it should
explicitly append the original value to the upgraded definition (explicitly
means writing it down in expanded form, like "/home/fis/.bin", not $HOME/.bin or
$VARIABLE_NAME). In the above bug, there is no way guix can define the
*XDG_DATA_DIRS* earlier than the distro. (You have to run the distro then
 install guix, right?). It's not perfect, but it seems to work.

I don't have any better idea for now. Does anybody know what kind of approaches
are employed by Flatpak and Snap?