If `select_from_ports` is evaluated lazily, we might miss a port during
the dependency check. A way to prevent this is to use the `:=` operator.
Fixesgenodelabs/genode#4618
Note, OpenSSL now comes as one combined depot archive *openssl* that
replaces the former *libssl* and *libcrypto* archives. The libraries are
still separate binaries for compatibility with legacy software.
Issue #3773
This patch changes the top-level directory layout as a preparatory
step for improving the tools for managing 3rd-party source codes.
The rationale is described in the issue referenced below.
Issue #1082