VA_DECL/VA_END usage

Make the variadic functions look more like ordinary code rather than
have the function opening brace be hidden inside the VA_DECL() macro.
That brace is still there, but VA_DECL() now needs to be followed by
a visible brace (which introduces a nested block rather than the
start of the funciton).  VA_END() now provides a hidden closing brace
to end the nested block, and the existing closing brace still matches
the one in VA_DECL().

Sample usage:
void foo VA_DECL(int, arg)  --macro expansion has a hidden opening brace
{  --new, explicit opening brace (actually introduces a nested block)
  VA_START(bar);
  ...code for foo...
  VA_END();  --expansion now provides a closing brace for the nested block
}  --existing closing brace, still pairs with the hidden one in VA_DECL()

This should help if/when another round of reformatting ever takes place,
and also with editors or other tools that do brace/bracket/parenthesis
matching.

I had forgotten that there were variadic functions in sys/* and ended
up modifying a lot more files than intended.  The majority of changes
to those just inserted a new '{' line so that revised VA_END()'s '}'
won't introduce a syntax error.  A couple of them needed VA_END() moved
so that local variables wouldn't go out of scope too soon.  Only the
Unix ones have been tested.

sys/amiga/amiwind.c

@@ -1,4 +1,4 @@
-/* NetHack 3.6	amiwind.c	$NHDT-Date: 1431192783 2015/05/09 17:33:03 $  $NHDT-Branch: master $:$NHDT-Revision: 1.8 $ */
+/* NetHack 3.6	amiwind.c	$NHDT-Date: 1431737059 2015/05/16 00:44:19 $  $NHDT-Branch: master $:$NHDT-Revision: 1.9 $ */
 /* NetHack 3.6	amiwind.c	$Date: 2009/05/06 10:48:30 $  $Revision: 1.5 $ */
 /*    SCCS Id: @(#)amiwind.c     3.5    2000/01/12
 /*    Copyright (c) Olaf Seibert (KosmoSoft), 1989, 1992	  */
@@ -889,6 +889,7 @@ amii_loadlib(void)
 /*VARARGS1*/
 void error
 VA_DECL(const char *, s)
+{
     VA_START(s);
     VA_INIT(s, char *);