USE_OLDARGS update (2 of 2)

Files modified:
include/extern.h
src/pline.c, priest.c, potion.c, mkobj.c

A bunch of calls to pline() in pline.c started triggering warnings
either as-is or possibly after the changes to tradstdc.h.  Fixing
them in place would include intrusive VA_PASSx() like in lev_main.c.
Moving them to other files is much simpler (and they didn't
particularly belong in pline.c in the first place, although I didn't
actually find any better place for them....).

The probing/stethoscope feedback went to priest.c, where there's a
comment stating that it should move to wherever englightenment ends
up once that is moved out of its completely inappropriate current
home in cmd.c.  (Holdover from when ^X was wizard-mode only but even
the other wizard mode commands don't really belong with the command
processing code.)

src/potion.c

@@ -1,4 +1,4 @@
-/* NetHack 3.6	potion.c	$NHDT-Date: 1455407631 2016/02/13 23:53:51 $  $NHDT-Branch: NetHack-3.6.0 $:$NHDT-Revision: 1.129 $ */
+/* NetHack 3.6	potion.c	$NHDT-Date: 1501725406 2017/08/03 01:56:46 $  $NHDT-Branch: NetHack-3.6.0 $:$NHDT-Revision: 1.137 $ */
 /* Copyright (c) Stichting Mathematisch Centrum, Amsterdam, 1985. */
 /* NetHack may be freely redistributed.  See license for details. */
 
@@ -408,6 +408,16 @@ boolean talk;
     }
 }
 
+void
+self_invis_message()
+{
+    pline("%s %s.",
+          Hallucination ? "Far out, man!  You"
+                        : "Gee!  All of a sudden, you",
+          See_invisible ? "can see right through yourself"
+                        : "can't see yourself");
+}
+
 STATIC_OVL void
 ghost_from_bottle()
 {