Fixing warnings under GCC4 in preparation to enable -Werror there as well:

* Replaced the use of offsetof() for structs that aren't PODs. Add a
  offset_of_member() macro to util/khash.h because that's what it's used for
  in our cases.
* Change the signature of add_debugger_command()/remove_debugger_command() on
  GCC > 2 to avoid the depricated conversion from string constants to char *.
* Adding some "suggested" parenthesis. I know that not everyone likes that, but
  it pointed out at least one bug that is fixed here as well.


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@29113 a95241bf-73f2-0310-859d-f6bbb57e9c96

src/system/kernel/kernel_daemon.cpp

@@ -83,7 +83,7 @@ KernelDaemon::Register(daemon_hook function, void* arg, int frequency)
 	if (function == NULL || frequency < 1)
 		return B_BAD_VALUE;
 
-	struct daemon* daemon = new(std::nothrow) struct ::daemon;
+	struct ::daemon* daemon = new(std::nothrow) (struct ::daemon);
 	if (daemon == NULL)
 		return B_NO_MEMORY;