We should move all public definitions in CMakeLists.txt to target_compile_definitions(opentelemetry_api INTERFACE ...)

[owent]

Describe your environment

System: Windows
Build System: cmake

Steps to reproduce

cmake <...> -DWITH_ETW=ON

What is the expected behavior?

Now, some definitions are added by add_definitions(...) in CMakeLists.txt and so that these definitions are private. But we should keep the same behaviour between compiling opentelemetry-cpp and using it by users. We can add these public definitions by target_compile_definitions(opentelemetry_api INTERFACE ...) and then these definitions will be auto passed to all cmake targets depend opentelemetry_api.

What is the actual behavior?

Some definitions are missing and library get a different behavior.

Additional context

Should we add prefix to NO_GETENV and NOMINMAX in case of them will conflict with other libraries?

It this's acceptable, it can be assigned to me please.

[owent]

Can I add OPENTELEMETRY_ prefix for NO_GETENV and NOMINMAX ?

[lalitb]

Can I add OPENTELEMETRY_ prefix for NO_GETENV and NOMINMAX ?

Just curious, why specifically for these two macro definitions, as we have lots of other definitions like HAVE_MSGPACK, HAVE_GSL.

[owent]

OK, I will just move the definitions into opentelemetry_api and dn not rename them.