Start moving 32-bit cruft somewhere it won't pollute 64-bit.

Change-Id: I03a6a50a5243f29e50fb58a3cf8b5e7198640baa

libc/bionic/wait.cpp

@@ -47,8 +47,3 @@ int waitid(idtype_t which, id_t id, siginfo_t* info, int options) {
   // The system call takes an optional struct rusage that we don't need.
   return __waitid(which, id, info, options, NULL);
 }
-
-// TODO: remove this backward compatibility hack (for jb-mr1 strace binaries).
-extern "C" pid_t __wait4(pid_t pid, int* status, int options, struct rusage* rusage) {
-  return wait4(pid, status, options, rusage);
-}