Suppress external dependency warnings

[linmajia]

Summary

Suppress noisy compiler warnings from the protobuf and thrift external builds, especially on macOS with newer Xcode SDKs.

Changes

• Pass additional non-Windows CXX warning suppressions to protobuf and thrift external CMake builds:
  • -Wno-unused-variable
  • -Wno-unused-parameter
  • -Wno-unused-but-set-variable
  • -Wno-unused-const-variable
  • -Wno-unused-private-field
  • -Wno-deprecated-declarations
• Preserve thrift’s BOOST_ERROR_CODE_HEADER_ONLY as a compiler definition when DSN_BOOST_HEADER_ONLY is enabled.
• Keep warning suppression in rDSN’s external-project CMake wrappers instead of modifying thrift/protobuf source.

Notes

These warnings come from old third-party dependency code and are harmless. This change only reduces build log noise; it does not change rDSN runtime behavior or generated code.

Testing

• Verified protobuf and thrift external CMake wrapper configuration locally.