Summary

Unify feature-flag macros into a shared header set in common_system and migrate all dependent repos to the normalized KCENON_* flags.

5W1H Specification

• Who: Core systems maintainers
• What: Consolidate feature-flag macros + standardize compiler/stdlib detection
• Where: common_system + dependent system repos
• When: TBD (per child issues)
• Why: Remove naming drift and duplicated detection logic
• How: Add unified headers, export KCENON_* via CMake, migrate code and docs

Scope

• In: Integration flags, compiler/stdlib feature detection, legacy alias window
• Out: Behavior changes and build system redesign

Child Issues

• Add unified feature_flags headers #224
• Adopt KCENON_* feature flags thread_system#333
• Use KCENON feature detection (jthread/source_location) logger_system#250
• Switch integration flags to KCENON_* network_system#335
• Use KCENON_HAS_COMMON_SYSTEM in container core container_system#180
• Use KCENON_HAS_MONITORING_SYSTEM messaging_system#163
• Adopt KCENON integration flags monitoring_system#271
• Normalize common_system integration flags database_system#277
• Normalize integration flags to KCENON_HAS_* database_server#23
• Replace PACS_WITH_COMMON_SYSTEM pacs_system#401
• Normalize logger/common flags file_trans_system#107

Acceptance Criteria

• common_system ships unified feature flag headers
• child repos use KCENON_* macros for integration gates
• legacy macros remain available for the migration window