Replace AcceptMutex, LockFile, RewriteLock, SSLMutex, SSLStaplingMutex, and WatchdogMutexPath with a single Mutex directive. Add APIs to simplify setup and user customization of APR proc and global mutexes. (See util_mutex.h.) Build-time setting DEFAULT_LOCKFILE is no longer respected; set DEFAULT_REL_RUNTIMEDIR instead.
Some existing modules, such as mod_ldap and mod_auth_digest gain configurability for their mutexes.