Set up for opentelemetry_proto_grpc_lib_type being shared

[tjcw]

Caution, this patch may cause one of the tests to go into a loop

Fixes #3126
Buildability for AIX

Changes

cmake/opentelemetry-proto.cmake to make opentelemetry_proto_grpc library link with gRPC::grpc++ if building shared

This PR split off from #3127

• CHANGELOG.md updated for non-trivial changes
• Unit tests have been added
• Changes in public API reviewed

[linux-foundation-easycla]

The committers listed above are authorized under a signed CLA.

• ✅ login: tjcw / name: Chris Ward (e8e31ec, 28a14a3)

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[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 87.85%. Comparing base (497eaf4) to head (e8e31ec).
Report is 161 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #3136      +/-   ##
==========================================
+ Coverage   87.12%   87.85%   +0.73%     
==========================================
  Files         200      195       -5     
  Lines        6109     6136      +27     
==========================================
+ Hits         5322     5390      +68     
+ Misses        787      746      -41     

see 100 files with indirect coverage changes

[DerrickLFX]

/easycla

[owent]

LGTM and thanks.

[marcalff]

The following CI:

CMake test (build shared libraries with otlp-exporter and static gRPC)

systematically fails on this test:

    Start  44: exporter.otlp.OtlpGrpcExporterFactoryTest.BuildTest

which hangs for up to 6 hours, and is then killed by the github infrastructure.

No explanations for the root cause at this point, but evidence from the recent CI runs in the opentelemetry-cpp repository seem to point at this change, as other branches do not show this.

It could be that this change is correct and exposed an existing bug elsewhere, or that somehow this change is incorrect / incomplete.

In any case, we need this resolved before merging, to avoid breaking CI.

[tjcw]

Asking a colleague, it seems we no longer use the function that is set up by this PR. So I can close it. Please reopen another matching PR if you want to investigate why it causes the CI test to go into a loop.