gnu-build-system should set DESTDIR

[John Darrington]

Per recent discussions:

I think the make install target in gnu-build-system should set DESTDIR to "/" 
(or "/.")
Rationale:

Many upstream makefiles (eg: 

https://git.gnome.org/browse/gnome-themes-standard/tree/themes/HighContrast/icons/Makefile.am)
 

assume that when DESTDIR is unset (or is "") then the package is being 
installed in a "live" system:

if test -z "$(DESTDIR)"; then \
                echo "Updating Gtk icon cache."; \
                $(gtk_update_icon_cache); \
else \
                echo "*** Icon cache not updated.  After (un)install, run 
this:"; \
                echo "***   $(gtk_update_icon_cache)"; \
fi

I have noticed that a number of packages in /nix/store/ have their own version 
of icon-theme.cache leading to warnings when doing guix package --install

So we need to set DESTDIR to *something* and to arrange for some kind of 
post-install hook to update
the cache.  The same goes for top level info nodes.

J'



-- 
PGP Public key ID: 1024D/2DE827B3 
fingerprint = 8797 A26D 0854 2EAB 0285  A290 8A67 719C 2DE8 27B3
See http://sks-keyservers.net or any PGP keyserver for public key.