add some unicode support (trunk only)

add some unicode support (trunk only)

This patch attempts to add some levels of unicode support
to NetHack.

The master on/off switch for any Unicode support is
defining UNICODE_SUPPORT in config.h. Currently
there is code support for two subsets of unicode support:

UNICODE_DRAWING

If UNICODE_DRAWING is defined, then the data
structures used to house drawing symbols are expanded
to the size of wchar_t, big enough to hold unicode characters.
A typdef called `nhsym' is involved and if UNICODE_DRAWING
is defined, it is wchar_t, otherwise it is uchar.

UNICODE_WIDEWINPORT

If UNICODE_WIDEWINPORT is defined, then the data
structures inside the window port are expanded to the size of
wchar_t, big enough to hold unicode characters.  Both map
symbols and text within the window port are expanded, in order
for potential support for displaying multinational characters some
day, but this patch only provides viewing of map symbols.
A typdef called `nhwchar' is involved and if UNICODE_WIDEWINPORT
is defined, it is wchar_t, otherwise it is char.

The only window port with code support for UNICODE_WIDEWINPORT
currently is the TTY port.  Don't enable UNICODE_WIDEWINPORT
unless:
- it is a TTY port
- the underlying platform specific routines can
handle the larger data structures.

Don't enable UNICODE_SUPPORT unless:
- your compiler can handle wchar_t.
- your compiler can accept L'a' characters.
- your compiler can accept L"wide" strings.

Note that if your compiler can handle the above, you could
enable the larger data structures (currently if TTY) even if your
platform can't actually display unicode or UTF-8, by messing
with u_putch() in win/tty/wintty.c to only deal regular chars.
That should be the only function that actually pushes wide characters
out to the display.

If you enable UNICODE_SUPPORT, and your platform is capable
you will need to turn on the unicode run-time option to be able to
load unicode character sets from the symbol file, to be able to
push unicode characters to the display. You'll also want to load
a unicode symbol set once the unicode option is toggled on. In
a config file you would do that via these two lines:
OPTIONS=unicode
OPTIONS=symset:Unicode_non_US

The repository was stamped with NETHACK_PRE_UNICODE
prior to applying this patch, and stamped with
NETHACK_POST_UNICODE afterwards. The code differences
between those two tagged versions are this patch.