Advanced Rogue family: overhaul privilege handling.

Advanced Rogue 5 and 7, and XRogue, now open the scorefile and logfile
at startup and then drop any set[ug]id privileges if the savedir is not
being used.

xrogue/state.c

@@ -3356,3 +3356,12 @@ md_setup()
     crmode();                        /* Cbreak mode */
     noecho();                           /* Echo off */
 }
+
+int
+md_normaluser(void)
+{
+#ifndef _WIN32
+    setuid(getuid());
+    setgid(getgid());
+#endif
+}