I would rather have just one version installed, but I gather that
removing the old version is going to break some of my currently
installed apps. (As I said, I temporarily removed just a few files
from /usr/lib/ and already lots of apps won't run.)
If you provided the new versions in /usr/local/lib and configured the
linker correctly, your apps should have used the gtk+-2.4. Since this
library is backward-compatible, this should just work.
from source, and glib/gtk is the only thing that consistently gives
me problems. I should be able to just have them installed in one
place, and upgrade them when they need it, without having to worry
about breaking all my apps or having to manage two separate
installations in two places.
Why don't you just do that then? If you have the old versions
installed from source in /usr, why do you put the new ones to
/usr/local ?