In TBB mutex'es are no longer copy constructable.

I don't think these need to be, either, so long as a new object gets default-constructed that can be locked.

From, https://www.threadingbuildingblocks.org/sites/default/files/resources/CHANGES_0.txt

Changes affecting backward compatibility:

- For compatibility with C++11 standard, copy and move constructors and
    assignment operators are disabled for all mutex classes. To allow
    the old behavior, use TBB_DEPRECATED_MUTEX_COPYING macro.