Add static-libs installation

[driverxdw]

add static library installation in CMakeLists.txt of libclamav submodules

[micahsnyder]

The code change makes sense to me and I can see this being useful if you want to statically link libclamav (and submodules) with some other program.

I'm running it through the test pipelines now.

[micahsnyder]

Manual testing on Linux looks good:

❯ ls -la install/lib/
total 42252
drwxr-xr-x 3 micah micah     4096 Nov 27 10:36 ./
drwxr-xr-x 8 micah micah     4096 Nov 27 10:36 ../
-rw-r--r-- 1 micah micah 38642020 Nov 27 10:36 libclamav_rust.a
-rw-r--r-- 1 micah micah  3696484 Nov 27 10:36 libclamav_static.a
-rw-r--r-- 1 micah micah   145808 Nov 27 10:35 libclammspack_static.a
-rw-r--r-- 1 micah micah    16110 Nov 27 10:35 libclamunrar_iface_static.a
-rw-r--r-- 1 micah micah   633086 Nov 27 10:35 libclamunrar_static.a
-rw-r--r-- 1 micah micah   108684 Nov 27 10:36 libfreshclam_static.a
drwxr-xr-x 2 micah micah     4096 Nov 27 10:36 pkgconfig/

[micahsnyder]

I found that the windows static build fails without these suggested changes.

[driverxdw]

I've fixed it, thank you for your suggestion!

[micahsnyder]

Looks good now, thanks!