Add a small dance to daemon() to reattach tmux to the user's namespace (which

allows access to the clipboard) on OS X 10.10 and above.

Chis Johnsen has done much work on and documentation of this issue, the code is
copied (with some tweaks) from his reattach-to-user-namespace at:

    https://github.com/ChrisJohnsen/tmux-MacOSX-pasteboard

Tested by Enrico Ghirardi.

Will see how this goes, if it breaks stuff it might go away again.

compat/daemon.c

@@ -28,12 +28,18 @@
  * SUCH DAMAGE.
  */
 
+#include <sys/types.h>
+
 #include <fcntl.h>
 #include <unistd.h>
 #include <stdlib.h>
 
 #include "compat.h"
 
+#ifdef __APPLE__
+extern void daemon_darwin(void);
+#endif
+
 int
 daemon(int nochdir, int noclose)
 {
@@ -61,5 +67,9 @@ daemon(int nochdir, int noclose)
 		if (fd > 2)
 			(void)close (fd);
 	}
+
+#ifdef __APPLE__
+	daemon_darwin();
+#endif
 	return (0);
 }