[protobuf] Should not build static libraries for x86-windows

[ras0219-msft]

No description provided.

[KindDragon]

Why static?

[ras0219-msft]

Sorry, the title isn't clear enough. The bug is that static libraries are currently being built when using the x86-windows triplet. That triplet should receive DLLs; the x86-windows-static triplet should receive static libraries.

The currently most robust way to test for whether to build static or DLL is the VCPKG_LIBRARY_LINKAGE property, as seen in https://github.com/Microsoft/vcpkg/blob/master/ports/zlib/portfile.cmake. This variable will be made available via the include(${CMAKE_TRIPLET_FILE}) directive, which pulls in the appropriate triplets\<tripletname>.cmake.

[KindDragon]

I remembered why I did it. I specifically build protobuf static library, otherwise, it was impossible to build grpc because of protocolbuffers/protobuf#2219

[ras0219-msft]

Given the general response in the protobuf thread, I'd be happy to apply protocolbuffers/protobuf#2227 locally if you'd be willing to submit a PR here with the diff for it as a patch (https://patch-diff.githubusercontent.com/raw/google/protobuf/pull/2227.diff).

[dzenanz]

protocolbuffers/protobuf#2227 has been merged on Dec 16th and protocolbuffers/protobuf#2219 was fixed on Dec 23rd. Can we get grpc #535 building, either static or DLLs?

[KindDragon]

IDK, maybe better wait for the release with this commit or apply commit as the patch to latest protobuf release.

[jozefizso]

Does protobuf support DLL linkage?

[KindDragon]

Yes