Turns on extra diagnostics related to libcwds threading critical areas. The checks are intended for developers who are changing internal locking or thread-lifetime code.
Never, unless you are a developer of libcwd. If someone requests it then I might extend this to a user interface however.
This is disabled by default. Use cmake -DEnableLibcwdDebug=ON -DEnableLibcwdDebugt=ON ... to enable it.