libcurl
Software gets updated, and some times, it seems, something just has to break
from it, and today I discovered that several of my Steam games had broken.
It turned out that they linked to a version of libcurl no longer on my system,
it had been removed during an update because it contains a security issue. Now,
I have the option of downgrading to the old version of curl, or wait for the
developers to recompile against a newer version of curl.. Had the source-code
been available, I (or even better, Steam) could have done this, but, I know
that's a bit too much to ask.. Anyway, it's kind of annoying.
