In this thread Oliver Hartmann describes an error he gets when compiling
the lib/libnv tests:
https://lists.freebsd.org/pipermail/freebsd-current/2015-March/054858.html
The errors are because the tests use the ATF_REQUIRE_EQ() macro with
NULL as its second argument, and the macro tries to output its arguments
on a std::ostringtream.
However, in C++11 you cannot output a plain NULL to any std::ostream;
you have to qualify the type of pointer by casting it. This is also
what ATF does internally for some of its tests.
I went through all the cases and added the correct casts, and now
lib/libnv can be successfully compiled with -std=c++11.