Thanks, moving protobuf ahead of the generic dependency prefixes looks right. Two small things before merging:

1. src/ now comes after protobuf. If protobuf sits in a shared prefix that also has an installed brpc, the installed butil//brpc/ headers will shadow the in-tree ones.

2. The test targets aren't covered yet. test/CMakeLists.txt:29 adds GPERFTOOLS_INCLUDE_DIR directly to brpc_test_config, so /opt/homebrew/include is still searched before protobuf when building unit tests. macOS CI doesn't build the tests, so it won't catch this.

Thank you! @darion-yaphet

Prepending the selected Protobuf include directory is a reasonable, scoped fix. It assumes that the directory belongs to a consistent dependency installation. Include ordering alone cannot guarantee correctness when shared prefixes contain conflicting versions of multiple libraries; that requires control over the build environment and dependency graph.

Keeping generated and in-tree brpc headers ahead of installed copies remains worthwhile, but I would treat that as a separate, limited concern rather than require this PR to solve general multi-version coexistence.

Since #3618 has merged, please rebase and adapt the change to the module-owned targets. A regression check with conflicting Protobuf headers in a generic prefix would help verify the intended behavior.