Fix c-ares compilation under Linux with dynamic linkage

[ahojnnes]

Describe the pull request

Without the changes in this PR, the Linux build fails under dynamic linkage with the following error:

Building package c-ares[core]:x64-linux...
-- Downloading https://github.com/c-ares/c-ares/archive/cares-1_17_1.tar.gz -> c-ares-c-ares-cares-1_17_1.tar.gz...
-- Extracting source .../downloads/c-ares-c-ares-cares-1_17_1.tar.gz
-- Using source at .../buildtrees/c-ares/src/res-1_17_1-7723edf4cb.clean
-- Configuring x64-linux-dbg
-- Configuring x64-linux-rel
-- Building x64-linux-dbg
-- Building x64-linux-rel
-- Installing: .../packages/c-ares_x64-linux/share/c-ares/copyright
-- Performing post-build validation
There should be no empty directories in .../packages/c-ares_x64-linux
The following empty directories were found:

• Which triplets are supported/not supported? Have you updated the CI baseline?

Yes

• Does your PR follow the maintainer guide?

Yes

• If you have added/updated a port: Have you run ./vcpkg x-add-version --all and committed the result?

Yes

[JackBoosY]

I can't repro this issue, did you use the official triplet x64-linux?
And can you please provide the install log buildtrees/c-ares/install-x64-linux-dbg-out.log ?

[ahojnnes]

Checked out latest master today, changed to dynamic linkage in the default x64-linux triplet (VCPKG_LIBRARY_LINKAGE dynamic) and then just ran vcpkg install c-ares:x64-linux. With shared linkage in the title, I meant dynamic linkage. Updated the title.