Brute-forced a set of changes which allowed
 make unicode-encapsulate
to work
 1) Patched make-mswin-unicode.pl to match macros with pointer return types;
 2) Updated intl-encap-win32.c to deal with
    a) added functions;
    b) refactoring of w32api include files.

Renamed DEVICE_TYPE to DEVICE_TYPE_X in device-impl.h and everywhere
it is used to avoid collision with DEVICE_TYPE in winioctl.h

Minimal fixes to get to compile wrt int vs. intptr_t in
 event-msw.c

event-msw.c:67:3: error: #error Something is wrong -- you are neither
Windows native (possibly MinGW) nor Cygwin.  # error Something is
wrong -- you are neither Windows native (possibly MinGW) nor Cygwin.

Ah, need a more up-to-date config.{sub,guess}, got one from somewhere
dated timestamp='2013-06-10'

Copy src/s/cygwin32.h to cygwin64.h and src/m/intel386.h to x86_64.h

And a configure.ac which recognises cygwin64
 
Remove cygwin_conv_to_posix_path from lib-src/gnuclient.c

Replace calls to qxeGetWindowLong(... GWL_..) with
qxeGetWindowLongPtr(... GWLP_...) (w. LONG_PTR result if used)
after re-making unicode-encapsulate
And one LONG l = qxeGetWindowLong (hwnd, XWL_FRAMEOBJ) to LONG_PTR l = qxeGetWindowLongPtr (hwnd, XWL_FRAMEOBJ)

Ah, several bugs in new header files in w32api, required some
additions to wfun_re in make-mswin-unicode.pl

That's enough to get event-msw.c to compile, although there are some
size-related warnings.

similar problem in frame-msw.c:
 qxeSetClassLong (FRAME_MSWINDOWS_HANDLE (f), GCL_HICON

and in glyphs-msw.c:
 qxeGetWindowLong
  (FRAME_MSWINDOWS_HANDLE (XFRAME (frame)),
   GWL_HINSTANCE),

and scrollbar-msw.c
also
      (void *) opaque =
	 (void *)qxeGetWindowLong (SCROLLBAR_MSW_HANDLE (sb), GWL_USERDATA);

        LONG_PTR opaque =
	 qxeGetWindowLongPtr (SCROLLBAR_MSW_HANDLE (sb), GWLP_USERDATA);

and dialog-msw.c:197:31: error: ‘DWL_USER’ undeclared (first use in this function)
       qxeSetWindowLong (hwnd, DWL_USER, l_param);

Compiles all the way through, links OK, temacs runs!
Build completes
xemacs -nw works
but xemacs as such does not:
 > ./xemacs
  Fatal error: assertion failed, file event-msw.c, line 4149, !NILP (Vmswindows_frame_being_created)
--------------
console-msw.c:116:3: warning: format '%ld' expects argument of type
'long int', but argument 3 has type 'DWORD' [-Wformat=]
 resolution: cast the DWORDs to long
----
event-msw.c: In function 'mswindows_wnd_proc':
event-msw.c:2741:6: warning: cast from pointer to integer of different size [-Wpointer-to-int-cast]
     ((LCID) GetKeyboardLayout (0) & 0xFFFF),
            cast to intptr_t first

event-msw.c:2825:50: warning: cast to pointer from integer of different size [-Wint-to-pointer-cast]
       virtual_key = qxeMapVirtualKeyEx (scan, 1, (HKL) lcid);
                                                     cast to intptr_t first
                                                  ^
event-msw.c:2839:6: warning: cast to pointer from integer of different size [-Wint-to-pointer-cast]
      (HKL) lcid);
     ^    ditto

event-msw.c:2861:7: warning: cast to pointer from integer of different size [-Wint-to-pointer-cast]
       (HKL) lcid);
       ^   ditto

[I _really_ don't understand the size hacking going on between LCIDs
  and HKLs here!]
event-msw.c: In function 'emacs_mswindows_remove_timeout':
event-msw.c:4200:6: warning: cast to pointer from integer of different size [-Wint-to-pointer-cast]
      (void *) id, MECR_DEALLOCATE_EVENT);
      ^
  This is a hack!!! Use intptr_t instead, still a hack.


frame-msw.c: In function ‘mswindows_init_frame_1’:
frame-msw.c:274:41: warning: cast from pointer to integer of different size [-Wpointer-to-int-cast]
  qxeSetWindowLong (hwnd, XWL_FRAMEOBJ, (LONG)STORE_LISP_IN_VOID (frame_obj));
                                          intptr_t

frame-msw.c: In function ‘mswindows_get_mouse_position’:
frame-msw.c:554:32: warning: cast to pointer from integer of different size [-Wint-to-pointer-cast]
   *frame = GET_LISP_FROM_VOID ((void *) qxeGetWindowLong (hwnd, XWL_FRAMEOBJ));
                                         qxeGetWindowLongPtr (hwnd, XWL_FRAMEOBJ

frame-msw.c: In function ‘mswindows_get_frame_parent’:
frame-msw.c:822:36: warning: cast to pointer from integer of different size [-Wint-to-pointer-cast]
       parent = GET_LISP_FROM_VOID ((void *) qxeGetWindowLong (hwnd, XWL_FRAMEOBJ));
             ditto

glyphs-msw.c: In function 'mswindows_widget_instantiate':
glyphs-msw.c:2261:8: warning: cast to pointer from integer of different size [-Wint-to-pointer-cast]
        (HMENU)id,       /* No menu */
  intptr_t id = -1;

menubar-msw.c: In function 'empty_menu':
menubar-msw.c:98:24: warning: cast from pointer to integer of different size [-Wpointer-to-int-cast]
 #define EMPTY_ITEM_ID ((UINT)STORE_LISP_IN_VOID (Qunbound))
menubar-msw.c:181:49: note: in expansion of macro 'EMPTY_ITEM_ID'
     qxeAppendMenu (menu, MF_STRING | MF_GRAYED, EMPTY_ITEM_ID,
 resolved:#define EMPTY_ITEM_ID ((UINT)STORE_LISP_IN_VOID (Qunbound))
                                intptr_t

dialog-msw.c:764:9: warning: passing argument 4 of 'qxeCreateDialogIndirectParam' from incompatible pointer type [enabled by default]
         (LPARAM) STORE_LISP_IN_VOID (obj));
         ^
          intptr_t

toolbar-msw.c: In function 'mswindows_clear_toolbar':
toolbar-msw.c:100:55: warning: cast from pointer to integer of different size [-Wpointer-to-int-cast]
       qxeSendMessage (toolbarwnd, TB_GETIMAGELIST, 0, (LONG) &ilist);
                                                       ^
                                                       intptr_t
toolbar-msw.c: In function 'mswindows_output_toolbar':
toolbar-msw.c:370:10: warning: cast to pointer from integer of different size [-Wint-to-pointer-cast]
          (HMENU)(TOOLBAR_ID_BIAS + pos),
          ^
                 (intptr_t)
In file included from mule-coding.c:32:0:
mule-coding.c: In function 'parse_charset_conversion_specs':

win32.c: In function 'mswindows_lisp_error_1':
win32.c:259:9: warning: format '%ld' expects argument of type 'long int', but argument 3 has type 'DWORD' [-Wformat=]
         errnum, GetLastError ());
         ^
                (long)
win32.c: In function 'Fmswindows_shell_execute':
win32.c:352:11: warning: cast from pointer to integer of different size [-Wpointer-to-int-cast]
     ret = (int) qxeShellExecute (NULL, opext, doc, parmext, path,
           ^
           intptr-t
win32.c: In function 'setitimer_helper':
win32.c:847:7: warning: passing argument 3 of 'timeSetEvent' from incompatible pointer type [enabled by default]
       event_type);
       ^
 resoluion: pblm is elsewhere?
  setitimer_helper_proc (UINT UNUSED (uID), UINT UNUSED (uMsg), DWORD[_PTR] dwUser,
		       DWORD[_PTR] UNUSED (dw1), DWORD[_PTR] UNUSED (dw2))

> make clean, try again

/usr/local/src/xemacs-21.5-64bit/lib-src/winclient.c: In function 'doFile':
/usr/local/src/xemacs-21.5-64bit/lib-src/winclient.c:299:4: warning: pointer targ
ets in passing argument 1 of 'DdeClientTransaction' differ in signedness [-Wpoint
er-sign]
    0, XTYP_EXECUTE, TRANSACTION_TIMEOUT, NULL);
    ^
In file included from /usr/local/src/xemacs-21.5-64bit/lib-src/winclient.c:27:0:
/usr/include/w32api/ddeml.h:208:19: note: expected 'LPBYTE' but argument is of ty
pe 'char *'
   HDDEDATA WINAPI DdeClientTransaction(LPBYTE pData,DWORD cbData,HCONV hConv,HSZ
 hszItem,UINT wFmt,UINT wType,DWORD dwTimeout,LPDWORD pdwResult);
                   ^
 [note it's arg1 that's the problem, cast to LPBYTE]

event-msw.c:4200:6: warning: passing argument 4 of 'map_event_chain_remove' makes pointer from integer without a cast [enabled by default]
      (intptr_t)id, MECR_DEALLOCATE_EVENT);
      ^
In file included from event-msw.c:72:0:
events.h:956:5: note: expected 'void *' but argument is of type 'long int'
 int map_event_chain_remove (int (*fn) (Lisp_Object ev, void *user_data),
 resolution: hack, but cast _again_, i.e. (void *)(intptr_t)

dialog-msw.c:764:9: warning: passing argument 4 of 'qxeCreateDialogIndirectParam' from incompatible pointer type [enabled by default]
         (intptr_t) STORE_LISP_IN_VOID (obj));
         ^
In file included from syswindows.h:642:0,
                 from console-msw.h:39,
                 from console-msw-impl.h:37,
                 from dialog-msw.c:37:
intl-auto-encap-win32.h:627:6: note: expected 'DLGPROC' but argument is of type 'BOOL (*)(struct HWND__ *, UINT,  WPARAM,  LPARAM)'
 HWND qxeCreateDialogIndirectParam (HINSTANCE hInstance, LPCDLGTEMPLATEW lpTemplate, HWND hWndParent, DLGPROC lpDialogFunc, LPARAM dwInitParam);
 resolved by adding a cast: (DLGPROC)dialog_proc, but not at all sure
that's right

> make clean, try again

intl-win32.c:1509:27: warning: cast to pointer from integer of different size [-Wint-to-pointer-cast]
     TranslateCharsetInfo ((DWORD *) (DWORD) old_logfont.lfCharSet, &info,
                           ^
 resolution: do nothing -- I think this is necessary because of
             extremely aggressive argument overloading by MS

intl-auto-encap-win32.c:126:5: warning: passing argument 1 of 'ShellExecuteExA' from incompatible pointer type [enabled by default]
     return ShellExecuteExA (pExecInfo);
     ^
In file included from syswindows.h:220:0,
                 from intl-auto-encap-win32.c:12:
/usr/include/w32api/shellapi.h:345:22: note: expected 'struct SHELLEXECUTEINFOA *' but argument is of type 'struct SHELLEXECUTEINFOW *'
   SHSTDAPI_(WINBOOL) ShellExecuteExA (SHELLEXECUTEINFOA *pExecInfo);
                      ^
 resolution: ignored, never used, removed from intl-encap-win32.c

intl-auto-encap-win32.c: In function 'qxeFreeEnvironmentStrings':
intl-auto-encap-win32.c:1771:5: warning: passing argument 1 of 'FreeEnvironmentStringsA' from incompatible pointer type [enabled by default]
     return FreeEnvironmentStringsA (penv);
     ^
In file included from /usr/include/w32api/winbase.h:28:0,
                 from /usr/include/w32api/windows.h:70,
                 from syswindows.h:204,
                 from intl-auto-encap-win32.c:12:
/usr/include/w32api/processenv.h:29:29: note: expected 'LPCH' but argument is of type 'LPWCH'
   WINBASEAPI WINBOOL WINAPI FreeEnvironmentStringsA (LPCH penv);
                             ^
intl-encap-win32.c: In function 'qxeUpdateICMRegKey':
intl-encap-win32.c:1426:36: warning: cast from pointer to integer of different size [-Wpointer-to-int-cast]
     return UpdateICMRegKeyW (arg1, (DWORD) arg2, (LPWSTR) arg3, arg4);
                                    ^
intl-encap-win32.c:1426:5: warning: passing argument 2 of 'UpdateICMRegKeyW' makes pointer from integer without a cast [enabled by default]
     return UpdateICMRegKeyW (arg1, (DWORD) arg2, (LPWSTR) arg3, arg4);
     ^
In file included from /usr/include/w32api/windows.h:71:0,
                 from syswindows.h:204,
                 from console-msw.h:39,
                 from intl-encap-win32.c:44:
/usr/include/w32api/wingdi.h:3425:28: note: expected 'LPWSTR' but argument is of type 'unsigned int'
   WINGDIAPI WINBOOL WINAPI UpdateICMRegKeyW(DWORD reserved,LPWSTR lpszCMID,LPWSTR lpszFileName,UINT command);
 resolution: nothing, known problem

Similarly wrt qxeEnumResourceTypes, qxeEnumResourceNames,
qxeEnumResourceLanguages, qxeImmSetCompositionString

---------
make clean, recompile, all looks OK, try to track down the problem --
the error in event-msw.c inside mswindow_find_frame, inside
intercepted_wnd_proc (a signal handler?),
where we have a
window with no frame saved, appears to happen when the main thread is
in mswindows_init_frame_1 at frame-msw.c:139
   at recompute_all_cached_specifiers_in_frame at specifier.c:3483
   at recompute_one_cached_specifier_in_frame at specifier.c:3444
    around the sixth one
---
April 2014 above here
----
After a tiny spark on interest on xemacs-beta, did pull -u, merge and
commit, make distclean, configure '--with-pdump=yes' '--with-modules=no' '--with-mule=yes' '--with-ncurses=yes' '--with-msw=yes' '--without-png' '--without-xpm' '--without-jpeg' '--with-cflags-debugging=-ggdb'

No change -- -nw works, w/o -nw gives the same assertion failed.
-----
Trying again, make distclean followed by 
 > 
didn't work!, had to add --without-x (why???)
------
Force debug printing on by
  debug_mswindows_events = 3;
at the end of event-msw.c
Added more printing, removed frame printing, from
debug_output_mswin_message ditto
Narrowed it down to the
   qxeSetWindowLong (hwnd, XWL_FRAMEOBJ, (intptr_t)STORE_LISP_IN_VOID (frame_obj));
at the end of mswindows_init_frame_1 in frame-msw.c
a) Should be ...LongtPtr
b) Not enough room allocated for a 64-bit long ptr -- fixed in
   console-msw-impl.h
----
Trying to get a clean diff to send to Vin
Need Change log entries!
Working with /c/C32/usr/local/src/xemacs-21.5-mine vs. -upstream (now
pulled from xemacs, not xemacs-beta)
_Only_ new files are 
 src/s/cygwin64.h
 src/m/x86_64.h
Changed files are
  > diff -rq --exclude=.hg --exclude=info --exclude=*.{o,i,exe,elc} xemacs-21.5-{upstream,mine}|egrep -v Only | cut -f 2 -d ' ' | cut -f 2- -d /
 ChangeLog
 README
 configure
 configure.ac
 lib-src/gnuclient.c
 lib-src/make-mswin-unicode.pl
 lib-src/winclient.c
 src/console-msw-impl.h
 src/console-msw.c
 src/device-impl.h
 src/device.c
 src/dialog-msw.c
 src/event-msw.c
 src/frame-msw.c
 src/frame.c
 src/glyphs-msw.c
 src/glyphs.c
 src/intl-auto-encap-win32.c
 src/intl-auto-encap-win32.h
 src/intl-encap-win32.c
 src/menubar-msw.c
 src/process-unix.c
 src/scrollbar-msw.c
 src/specifier.c
 src/toolbar-msw.c
 src/win32.c
---
default branch, abandoned cygwin64 as system-type
Trying to compile with vs2015:

  > patch -p 1 < ../xemacs-21.5-upstream/vs2015_3.patch
  patching file nt/xemacs.mak
  Hunk #4 FAILED at 796.
  1 out of 19 hunks FAILED -- saving rejects to file nt/xemacs.mak.rej
  patching file src/intl-auto-encap-win32.c
  Hunk #1 FAILED at 36.
  Hunk #2 succeeded at 3147 with fuzz 2 (offset -199 lines).
  Hunk #3 succeeded at 3156 with fuzz 2 (offset -199 lines).
  1 out of 3 hunks FAILED -- saving rejects to file src/intl-auto-encap-win32.c.rej
  patching file src/s/windowsnt.h
  patching file src/sysproc.h
OK, did first (.mak) by hand, other was there, in a different place,
already.
Compilation produces _lots_ of warnings about type/size conversions,
slowly figuring out fixes, possible not all correct :-(
Some further forward and back hacking wrt timeval and tv_sec, finally
had to actually edit /c/Program Files (x86)/Windows
Kits/8.1/Include/um/winsock.h to get things moving :-(

Lots of EMACS_INT (long long) == 8-bytes -> int or long == 4-bytes
warnings, whose equivalent (long (8) -> int (4)) are _not_ notified by
Cygwin, are coming up, sort-of overpowering the compiler output, so
fttb I've set ERROR_CHECK_ALL=0 in config.inc, which turned off -TP
(CPP, which I thought was raising the warnings), but still getting many
warnings: down from 567 to 423!
More small fixes, in process-nt.c very speculative, get me to through
compilation to (lots of) linking errors
Clean and rebuild and only Xpm lib linking errors, turn off Xpm and
build completes except for makeinfo (shell script pblm)

Using VS for the winlibs, to set flags etc. use the wrench icon in the
Property Manager window.
Copied all but WIN32 preprocessor flag from the 32-bit VS-built
solution.
Needed to fuss with linker debugging flags and input (module
definition file) to get it all to work for Xpm, but now it does!
Installs under Program Files, but not finding packages despite
load-path being
  ("c:\\C64\\home\\ht\\lib\\emacs\\" "c:/C64/usr/local/share/xemacs/xemacs-packages/lisp" "c:\\Program Files\\XEmacs\\XEmacs-21.5-b34\\lisp\\")

Backed out change to winsock.h, and updated corresponding comments in
systime.h

Now getting 2192 conversion warnings, makes me v. nervous!

But it runs. . .