Summary

Remove the gcp_store cloud storage extension and all associated build, CI, and test references.

Files to delete

• ext/storage_sources/gcp_store/ (entire directory including tests)
• cmake/third_party/gcp_sdk.cmake

Build system changes

• CMakeLists.txt:66 — remove include(cmake/third_party/gcp_sdk.cmake)
• ext/CMakeLists.txt:34-36 — remove if(ENABLE_GCP) add_subdirectory(storage_sources/gcp_store) block

Evergreen CI (test/evergreen.yml)

• Remove ENABLE_GCP variable (~line 1590)
• Remove ${ENABLE_GCP|} from cmake flags block (~line 326)
• The azure-gcp-* Evergreen tasks are shared with Azure — once both azure_store and gcp_store tickets are merged, those tasks are fully gone (coordinate with the azure_store ticket)

Python test suite

• test/suite/helper_tiered.py — remove gcp_store branch in get_auth_token(), remove gcp_store entry in bucket dict, remove gcp_store scenario tuple, remove gcp_store branch in create_bucket()