openssl: link enough files for the legacy provider to actually load

[glebius]

To test try openssl list -provider legacy

[khorben]

I offered the same patch in D51897, with:

• my own concerns in https://reviews.freebsd.org/D51897#1186112 that legacy.so should not need params_idx.c
• ngie offering another series of changes instead (see D52009)

In spite of that, it looks good enough to me in the meantime to close the gap; @ngie did not accept the changes offered there though.

[glebius]

In D52113#1191381, @khorben wrote:

In spite of that, it looks good enough to me in the meantime to close the gap; @ngie did not accept the changes offered there though.

@ngie may I commit what I have to get regressed CURRENT fixed ASAP? And then you do your automated process, which of course is welcome.