After this change, the default for dynamic libraries (`-l` or
`--library`) is to only link them if they end up being actually used.

With the Zig CLI, the new options `-needed-l` or `--needed-library` can
be used to force link against a dynamic library.

With `zig cc`, this behavior can be overridden with `-Wl,--no-as-needed`
(and restored with `-Wl,--as-needed`).

Closes #10164