[cld3] Cleanup, use protobuf config

[dg0yt]

By-product of reviewing #35781.

• Splits build fixes from unofficial config patch.
• Switches to Protobuf CMake config (as desired for protobuf update in [grpc/protobuf] Update grpc to 1.60.0 and update protobuf to 3.25.1 #35781, needed for abseil dependency).
• Fixes compiler options, in particular c++ standard.
• Use standard MSVC guards.

Not upstreaming the changes due to inactivity. google/cld3#85 (comment).

[jimwang118]

Usage test pass with following triplets:

x86-windows
x64-windows
x64-windows-static

[BillyONeal]

Thanks for the fixes! Thanks for checking up with upstream!