CMake defaults to the current directory if the source or build
directory is not specified. Harfbuzz builds into an alternate
directory so it fails. This change specifies the directory prior
to any additional parameters so the build can succeed with
cmake 3.18.4.
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.
