Support building Emacs on MS-Windows using the Posix configury.

Support building Emacs on MS-Windows using the Posix configury.

 lib/Makefile.am: If building for MS-Windows, include
 nt/gnulib.mk instead of lib/gnulib.mk.
 configure.ac: Adapt to MSYS build on MS-Windows.
 Makefile.in (NTDIR): New variable, for the MSYS build on
 MS-Windows.
 (SUBDIR): Add $(NTDIR).
 (.PHONY): Add epaths-force-w32.
 (msys_to_w32): New variable.
 (epaths-force-w32, install-nt, uninstall-nt): New targets.
 (lib-src src): Add $(NTLIB) to prerequisites.
 (lib lib-src lisp leim nt): Add 'nt'.
 (config.status): Use $(CFG).
 (.PHONY): Add install-$(NTDIR) and uninstall-$(NTDIR).
 (install, install-arch-dep): Add install-$(NTDIR).
 (uninstall): Depend on uninstall-$(NTDIR).
 (mostlyclean, clean, distclean, bootstrap-clean): Add 'nt'.
 * GNUmakefile (CFG): New variable, uses mingw-cfg.site as
 CONFIG_SITE for the MSYS build on MS-Windows.
 (Makefile): Use $(CFG).
 .bzrignore: Ignore *.res, *.tmp, and *.map.  Remove
 src/emacs.res.

 etc/NEWS: Advertise the MSYS build on MS-Windows.

 leim/Makefile.in (leim-list.el, check-declare): Use reveal-filename.

 lib-src/update-game-score.c [WINDOWSNT]: Include "ntlib.h".
 lib-src/ntlib.h (sleep): Update prototype.
 (geteuid): Add prototype.
 lib-src/ntlib.c (sleep): Now returns an unsigned value.
 (getgid): New function.
 lib-src/Makefile.in (CLIENTW, LIB_WSOCK32, LIBS_ECLIENT, NTLIB)
 (CLIENTRES, WINDRES, NTINC, NTDEPS): New variables.
 (INSTALLABLES): Add $(CLIENTW).
 (LIBS_MOVE): Use $(LIB_WSOCK32).
 ($(DESTDIR)${archlibdir}): Use $(EXEEXT) on update-game-score.
 (test-distrib${EXEEXT}): Use $(EXEEXT) on test-distrib.
 (etags${EXEEXT}, ebrowse${EXEEXT}, ctags${EXEEXT})
 (profile${EXEEXT}, make-docfile${EXEEXT}, movemail${EXEEXT})
 (emacsclient${EXEEXT}, hexl${EXEEXT}, update-game-score${EXEEXT}):
 Add $(NTLIB) to prerequisites.  Use $(EXEEXT).
 (pop.o): Add pop.h to prerequisites.
 (emacsclientw${EXEEXT}, ntlib.o): New targets.
 (emacsclient.res): New target.

 lisp/subr.el (reveal-filename): New function.
 lisp/loadup.el: Compute Emacs executable versions on MS-Windows,
 where executables have the .exe extension.  Add a hard link
 emacs-XX.YY.ZZ.exe on MS-Windows.
 lisp/Makefile.in (XARGS_LIMIT): New variable.
 (custom-deps, finder-data, autoloads)
 ($(MH_E_DIR)/mh-loaddefs.el, $(TRAMP_DIR)/tramp-loaddefs.el)
 ($(CAL_DIR)/cal-loaddefs.el, $(CAL_DIR)/diary-loaddefs.el)
 ($(CAL_DIR)/hol-loaddefs.el): Use reveal-filename.
 (compile-main): Limit xargs according to $(XARGS_LIMIT).

 nt/msysconfig.sh: New file.
 nt/mingw-cfg.site: New file.
 nt/makefile.w32-in (LOCAL_FLAGS): Add -DOLD_PATHS=1.
 nt/inc/unistd.h: Include pwd.h and sys/types.h.
 nt/inc/sys/time.h (_TIMEVAL_DEFINED, timerisset, timercmp)
 (timerclear): Define.
 (gettimeofday): Adjust signature to be Posix compatible, by using
 the 'restrict' keyword.
 nt/inc/sys/stat.h (UTIME_NOW, UTIME_OMIT): Define.
 (struct _stat, struct _stati64): Define.
 nt/inc/sys/socket.h (timeval): Define only for MSVC.
 (FD_SET, FD_CLR, FD_ISSET, fd_set): Redefine only if
 EMACS_CONFIG_H is defined.
 (timeval): Undefine only for MSVC.
 nt/inc/ms-w32.h (HAVE___BUILTIN_UNWIND_INIT, restrict)
 (HAVE_WINDOW_SYSTEM, HAVE_MENUS, EMACS_CONFIGURATION)
 (EMACS_CONFIG_OPTIONS, HAVE_LONG_LONG_INT)
 (HAVE_UNSIGNED_LONG_LONG_INT): Define only if not already defined.
 (fileno): Move definition after including stdio.h.
 (sigset_t): Guard typedef by _W64.
 nt/gnulib.mk: New file.
 nt/epaths.nt: New file.
 nt/addpm.c [!OLD_PATHS]: Include src/epaths.h, instead of having a
 copy of the file names there.
 <env_vars> [!OLD_PATHS]: Use macros from epaths.h instead of
 literal strings.
 nt/Makefile.in: New file.
 nt/INSTALL.MSYS: New file.
 nt/INSTALL: Mention INSTALL.MSYS.

 src/w32.c: Include epaths.h.
 (init_environment): Use cmdproxy.exe without leading directories.
 Support emacs.exe in src; point SHELL to cmdproxy in ../nt in that
 case.
 (gettimeofday): Adjust signature and return value to Posix
 expectations.
 src/unexw32.c (open_output_file): Delete the existing emacs.exe
 before creating it, to break the hard link to the versioned
 executable.
 src/Makefile.in (EMACS_MANIFEST, CM_OBJ, TEMACS_POST_LINK)
 (ADDSECTION, EMACS_HEAPSIZE, MINGW_TEMACS_POST_LINK)
 (FIRSTFILE_OBJ): New variables.
 (W32_RES): Rename to EMACSRES.  All users changed.
 (base_obj): Use $(CM_OBJ).
 (ALLOBJS): Use $(FIRSTFILE_OBJ).
 (emacs$(EXEEXT)): Depend on $(ADDSECTION).
 (temacs$(EXEEXT)): Use $(TEMACS_POST_LINK), and move
 $(W32_RES_LINK) before $(LIBES).
 (emacs.res): Depend on $(EMACS_MANIFEST).  Put emacs.rc in nt.