auth: don't build .so for non-dyn modules

[Habbie]

Short description

fixes #14027

Checklist

I have:

• read the CONTRIBUTING.md document
• compiled this code
• tested this code
• included documentation (including possible behaviour changes)
• documented the code
• added or modified regression test(s)
• added or modified unit test(s)
• checked that this code was merged to master

[Habbie]

I am not sure we need the dependency LD flags on the static version. On the other hand, having them might allow us to use libtool to find our statically linkable modules during the build without the OBJECTFILES/OBJECTLIBS hack - but as we hope to just switch to Meson soon, I'm not going to put more effort in.

[Habbie]

markes as draft because I want to test package builds (once this PR itself turns green)

[coveralls]

Pull Request Test Coverage Report for Build 10901395890

Warning: This coverage report may be inaccurate.

This pull request's base commit is no longer the HEAD commit of its target branch. This means it includes changes from outside the original pull request, including, potentially, unrelated coverage changes.

• For more information on this, see Tracking coverage changes with pull request builds.
• To avoid this issue with future PRs, see these Recommended CI Configurations.
• For a quick fix, rebase this PR at GitHub. Your next report should be accurate.

Details

• 0 of 0 changed or added relevant lines in 0 files are covered.
• 93 unchanged lines in 14 files lost coverage.
• Overall coverage decreased (-0.002%) to 64.705%

---

Files with Coverage Reduction	New Missed Lines	%
modules/gpgsqlbackend/gpgsqlbackend.cc	1	88.62%
pdns/misc.cc	1	63.83%
pdns/validate.cc	1	68.09%
pdns/recursordist/aggressive_nsec.cc	2	66.1%
pdns/distributor.hh	2	51.86%
modules/lmdbbackend/lmdbbackend.cc	2	73.5%
pdns/recursordist/recpacketcache.hh	3	89.55%
modules/gpgsqlbackend/spgsql.cc	3	67.46%
pdns/dnsdistdist/dnsdist-carbon.cc	6	62.43%
pdns/packethandler.cc	8	72.74%

Totals
Change from base Build 10882883877:	-0.002%
Covered Lines:	124869
Relevant Lines:	162272

---

💛 - Coveralls

[Habbie]

markes as draft because I want to test package builds (once this PR itself turns green)

https://github.com/Habbie/pdns/actions/runs/10939385287

[Habbie]

packages look unchanged, and work

[zeha]

LGTM, and I hope meson is around the corner 🚀