USE_OLDARGS update (1 of 2)

Files modified:
    include/tradstdc.h, sp_lev.h, system.h
    util/lev_main.c

Silence a bunch of warnings generated by recent gcc which weren't there
with whatever version I had when 3.6.0 was being readied for release.
For lev_main, there were two basic types:  not enough arguments in calls
to lc_pline, lc_warning, and lc_error (since we weren't passing dummy
arguments as is done for add_opvars), and conversion from 'int' or
narrower to 'char *' (from -Wint-to-pointer-cast, which either wasn't
there yet in the older gcc, or wasn't included in -Wall back then).
[Note that for any configuration decrepit enough to actually need
USE_OLDARGS, such conversions will either work fine or else nethack
simply won't be viable.]

src/pline.c generates a bunch of warnings (for USE_OLDARGS).  The fix
for that will be (2 of 2).

To test, instead of mucking about with CFLAGS or sys/unix/hints, I've
been temporarily adding unconditional
|#undef USE_STDARG
|#undef USE_VARARGS
|#define USE_OLDARGS
to the end of config1.h and then doing my normal build--which is why
-Wall (or possibly -W) is drawing -Wint-to-pointer-cast warnings.

include/system.h

@@ -1,4 +1,4 @@
-/* NetHack 3.6	system.h	$NHDT-Date: 1449269772 2015/12/04 22:56:12 $  $NHDT-Branch: NetHack-3.6.0 $:$NHDT-Revision: 1.12 $ */
+/* NetHack 3.6	system.h	$NHDT-Date: 1501723401 2017/08/03 01:23:21 $  $NHDT-Branch: NetHack-3.6.0 $:$NHDT-Revision: 1.13 $ */
 /* Copyright (c) Stichting Mathematisch Centrum, Amsterdam, 1985. */
 /* NetHack may be freely redistributed.  See license for details. */
 
@@ -489,8 +489,17 @@ E int FDECL(vprintf, (const char *, va_list));
 #endif
 #endif
 #else
+#ifdef vprintf
+#undef vprintf
+#endif
 #define vprintf printf
+#ifdef vfprintf
+#undef vfprintf
+#endif
 #define vfprintf fprintf
+#ifdef vsprintf
+#undef vsprintf
+#endif
 #define vsprintf sprintf
 #endif
 #endif /* NEED_VARARGS */