So... I updated from 3.0.1 to 3.1... Now, since I am having trouble
  rebuilding specifically updated packages (nspr, for example, which now
  generates errors in recompiling some parts of Gnome)... I would like
  to force a recompile of all the installed packages...

You can also use the new pkg_rolling-replace, and set rebuild=YES on
all the gnome packages.  Actually setting rebuild=YES on glib is
probably enough to rebuild almost everything.


This is similar to pkg_chk, but your system should remain largely
usable, except for issues caused by upgrading packages with shlib
bumps.