While using sed can be handy to use for a quick-fix, these instances
accumulate, and can become unmaintainable. Not only that, but using sed
isn't necessarily robust and it can fail silently. Most of our usage is
also missing any documentation explaining why something is being done,
when it should be updated/removed etc.

Rather than relying on sed going forward, where possible, I've converted
our sed usage into patches. These are easier to maintain, contain
documentation, and should fail loudly when they don't apply.

The remaining sed usage, (1 in miniupnpc, the rest in qt), are
non-trivial to remove, as they are using build-time variables, or some
input from the environment.

make build-all