enable USE_WIN_IOCTL code unless explicitly avoided

Changes to be committed:
	modified:   doc/fixes36.1
	modified:   include/unixconf.h
	modified:   sys/share/ioctl.c

github pull request #19 made reference to resulting code behaviour
being better when windows were resized when USE_WIN_IOCTL was defined.

The logic for including the necessary enabling code in the build in
sys/share/ioctl.c was an explicit "opt-in" strategy, so anything not
deliberately and explicitly listed was not able to take advantae
of the potentially useful code. The need to add #defines to that
list would have been perpetual as new platforms came online, and
unnecessarily restrictive for everything else.

This switches the logic to include the code by default now,
and thus
unless there is an explicit "opt-out" by uncommenting
AVOID_WIN_IOCTL in include/unixconf.h

Some platforms, and we have no way of knowing which ones, may have
to ensure that AVOID_WIN_IOCTL is #define'd.

sys/share/ioctl.c

@@ -1,4 +1,4 @@
-/* NetHack 3.6	ioctl.c	$NHDT-Date: 1432512788 2015/05/25 00:13:08 $  $NHDT-Branch: master $:$NHDT-Revision: 1.12 $ */
+/* NetHack 3.6	ioctl.c	$NHDT-Date: 1520099308 2018/03/03 17:48:28 $  $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. */
 
@@ -63,9 +63,12 @@ struct termio termio;
 #include <signal.h>
 #endif
 
-#if defined(TIOCGWINSZ)                                    \
-    && (defined(BSD) || defined(ULTRIX) || defined(AIX_31) \
-        || defined(_BULL_SOURCE) || defined(SVR4))
+/* AVOID_WIN_IOCTL can be uncommented in unixconf.h
+ * to force USE_WIN_IOTCL to remain undefined,
+ * instead of the restricted explicit opt-in
+ * logic that used to be here.
+ */
+#if defined(TIOCGWINSZ) && !defined(AVOID_WIN_IOCTL)
 #define USE_WIN_IOCTL
 #include "tcap.h" /* for LI and CO */
 #endif