gRPC appears to only link against static CRT

[IIFE]

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Is your feature request related to a problem? Please describe.
the gRPC port appears to build gRPC against static CRT using the following option:
-DgRPC_MSVC_STATIC_RUNTIME=${gRPC_MSVC_STATIC_RUNTIME}

This is problematic when consuming the gRPC libraries in a solution that only relies on the dynamic CRT.

In my triplet override I am specifying set(VCPKG_CRT_LINKAGE dynamic), however I believe that is getting ignored by the -DgRPC_MSVC_STATIC_RUNTIME=${gRPC_MSVC_STATIC_RUNTIME} option.

Proposed solution
Allow gRPC to be built against dynamic CRT.

Describe alternatives you've considered
I am thinking of changing the port to link against dynamic CRT, however I'm not sure how to best do that as I'm not familiar with the side effects of the gRPC options.

Additional context
Visual Studio 2015, Windows.

[IIFE]

Strangely, which I run dumpbin /DIRECTIVES grpc.lib it shows /DEFAULTLIB:MSVCRT. What does the -DgRPC_MSVC_STATIC_RUNTIME=${gRPC_MSVC_STATIC_RUNTIME} option actually do, as I think I'm getting confused by it.

[IIFE]

Furthermore, any reason gRPC is only built as static lib. Following option in port file appears to indicate so:
vcpkg_check_linkage(ONLY_STATIC_LIBRARY)

[LilyWangL]

Thanks for posting this issue. Due to grpc has problems with exporting symbols, it only support static build. You can get more information from: #539 #535

[IIFE]

@LilyWangL Thanks for your reply.

OK that's no problem if it builds as a static lib. However, I just want to confirm my understanding. gRPC is built as a static lib, however it's linked against the dynamic CRT, correct?

Thanks.

[LilyWangL]

If you build grpc:x86-windows, you will get a static lib and it's linked the dynamic CRT.

[IIFE]

Thanks for the confirmation.