make CxxUtils/unused.h usable from a C89 compilation unit


git-svn-id: svn+ssh://svn.cern.ch/reps/atlasoff/Control/CxxUtils/trunk@539531 4525493e-7705-40b1-a816-d608a930855b
Add copy_bounded.


git-svn-id: svn+ssh://svn.cern.ch/reps/atlasoff/Control/CxxUtils/trunk@540349 4525493e-7705-40b1-a816-d608a930855b