The last file, i.e. the one you are compiling, is the interesting one.
In file included from /usr/include/c++/3.3/backward/warn.h:4,
- from /usr/include/c++/3.3/backward/iostream.h:31,
+ from /usr/include/c++/3.3/backward/iostream.h:31:0,
from test_clt.cc:1: