In 43c27e8, I mistakenly deleted the patch that removed calls to the
statfs() function, which we do not have. This made building the port
with a clean source tree fail.
This commit changes `libuv` to use our statvfs() function instead.
We may need entries with spaces in makeopts, installopts, and
configopts, and at that point we should also convert depends and
auth_opts to avoid confusion.
Now that we're generating the CMake toolchain file in the build
directory, we need to redirect the ports that use CMake to the new
location. Looking into this showed that there's still a bunch of work to
do in general to make the ports agnostic to which toolchain they're
using, there's a lot of hard-coded ${ARCH}-pc-serenity-gcc assumptions
still here.
We've had a half-arsed port of libuv inside the cmake port, but let's
just port it properly.
Note that this pins a specific commit (which is currently the latest
commit in their default branch).
