Remove/fix unused stuff and other warnings

user/tb/interp.c

@@ -238,6 +238,5 @@ next:
     line = string_tokenizealloc(NULL, "\n");
   }
 
-done:
   return ok;
 }

user/tb/runtime.c

@@ -79,6 +79,7 @@ bool rt_mkalias(Token *tks) {
 }
 
 bool rt_PID(Token *tks) {
+  (void)tks;
   uprintf("%lu\n", PID);
   return true;
 }