gistfile1.txt

ryoqun@mizuna:~/rubinius-with-clang$ clang++ -c /tmp/name.cpp 
/tmp/name.cpp:3:11: error: redefinition of 'thread' as different kind of symbol
namespace thread {
          ^
/tmp/name.cpp:1:8: note: previous definition is here
struct thread;
       ^
1 error generated.
ryoqun@mizuna:~/rubinius-with-clang$ g++ -c /tmp/name.cpp 
/tmp/name.cpp:3:18: error: ‘namespace thread { }’ redeclared as different kind of symbol
/tmp/name.cpp:1:8: error: previous declaration of ‘struct thread’
ryoqun@mizuna:~/rubinius-with-clang$ cat /tmp/name.cpp 
struct thread;

namespace thread {
};