vector is being built even with `--no-dph`
I usually use
./sync-all --no-dph get to speed up things a bit. But packages
random are still being pulled (by virtue of being submodules), and then built.
It would be nice if the build system would build them only if
libraries/dph is available, or have another way of making them optional.
(Potentially obsolete once #8545 (closed) is done.)