suppress c++11 warnings on darwin

git-svn-id: svn://svn.code.sf.net/p/libtorrent/code/branches/RC_1_0@10392 a83610d8-ad2a-0410-a6ab-fc0612d85776
make test_checking.cpp a bit nicer

git-svn-id: svn://svn.code.sf.net/p/libtorrent/code/branches/RC_1_0@10393 a83610d8-ad2a-0410-a6ab-fc0612d85776